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PLOS One logoLink to PLOS One
. 2022 Jan 31;17(1):e0247637. doi: 10.1371/journal.pone.0247637

Efficacy of Wang Nam Yen herbal tea on human milk production: A randomized controlled trial

Koollachart Saejueng 1, Tanawin Nopsopon 2, Piyawadee Wuttikonsammakit 3, Wattanaporn Khumbun 4, Krit Pongpirul 2,5,*
Editor: Jacqueline J Ho6
PMCID: PMC8803155  PMID: 35100251

Abstract

Background

Insufficient milk production is a common problem affecting breastfeeding women, in particular following Cesarean delivery. Wang Nam Yen herbal tea is a promising traditional Thai medicine used by postpartum women to stimulate milk production, as an alternative to pharmaceutical galactagogues. We aimed to compare the efficacy of Wang Nam Yen herbal tea, domperidone, and placebo, in increasing milk production in mothers who underwent Cesarean delivery.

Methods

Women who underwent uncomplicated cesarean delivery at Sunpasitthiprasong Hospital were randomized into three groups. The participants received the treatments daily for three consecutive days. The primary outcome was breast milk volume at 72 hours after delivery. Secondary outcomes were pregnancy and neonatal outcomes, adverse events, and participant satisfaction.

Results

Of the 1,450 pregnant women that underwent cesarean delivery, 120 women were enrolled. Their mean age and gestational ages were 28.7 years and 38.4 weeks, respectively. Breast milk volume at 72 hours postpartum was significantly different among the three groups (p = 0.030). The post hoc Bonferroni correction indicated a significant difference in breast milk volume between Wang Nam Yen herbal tea group and placebo control group (p = 0.007) while there was no difference between Wang Nam Yen herbal tea group and domperidone group (p = 0.806) and between domperidone group and placebo control group (p = 0.018). There was no difference in pregnancy and neonatal outcomes, adverse events, and participant satisfaction among the three groups.

Conclusion

Wang Nam Yen herbal tea was effective in augmenting breast milk production at 72 hours postpartum in mothers following cesarean delivery, and there was no evidence that herbal tea and domperidone differed in terms of augmenting breast milk production.

Trial registration

The study was approved by the institutional review board of Sunpasitthiprasong Hospital (No.061/2559) and was registered TCTR20170811003 with the Thai Clinical Trial Registry.

Introduction

Breastfeeding advantages are well documented and considered the normative and recommended standard for infant nutrition [1, 2]. Women who undergone cesarean deliveries have a risk of inadequate breast milk production [1]. Low production of breast milk is one of the most common causes of inadequate breastfeeding, which could be supported through various techniques, including the use of substances that stimulate the production of breast milk, known as galactagogues [1, 2]. Domperidone is a commonly prescribed galactagogue, which promotes breast milk production in women experiencing low breast milk supply, with low levels of transfer to maternal milk and no substantial alterations in the nutrient composition [3–6]. The lactogenic effect of domperidone could be as early as two hours after ingestion measured by prolactin level [7], while other studies showed significant effects after 24 hours of treatment measured by prolactin level [8], and daily milk volume [9]. Despite no side-effects being reported in infants of mothers who had used domperidone, domperidone was controversial and had never been approved for marketing by the US FDA due to the potential increased risk of ventricular arrhythmia and sudden cardiac death in adults [2, 10, 11].

As an alternative to pharmaceutical products, several complementary and alternative techniques could be used as galactagogues [12]. Herbal medicines and techniques including herbal compression, herbal supplements, and herbal teas containing ginger, stinging nettle, fenugreek, or turmeric, are effective for promoting breast milk production without adverse effects [13–16]. In Thailand, numerous traditional galactagogues, including banana flower, lemon basil, Thai basil, bottle gourd, and pumpkin, have significant correlations with increased breast milk volume [17].

Several factors are associated with inadequate breastfeeding due to low milk production, including cesarean deliveries which can lead to lactation difficulties [1, 2, 9]. Postpartum treatment with Domperidone in women who have undergone full-term cesarean has shown augmented production of breast milk [9]. At Wang Nam Yen hospital in Thailand, the Wang Nam Yen herbal tea, consisting of sappan (Caesalpinia sappan Linn.), licorice (Glycyrrhiza glabra Linn.), bael fruit (Aegle marmelos L. Corr), ginger (Zingiber officinale Roscoe), and jewel vine (Derris scandens (Roxb.) Benth) have been used as a traditional Thai medicine to stimulate milk production in postpartum women. Wang Nam Yen herbal tea is expected to provide a lactogenic effect as early as 24 hours after first ingested and a significant effect at 72 hours of ingestion as presented in a previously unpublished study measured by daily milk volume [18].

The most active galactagogue ingredient in Wang Nam Yen hospital is ginger which has evidence on lactogenic effect as a single treatment after 48–72 hours of ingestion measured by daily milk volume [16], and as combined treatment with other herbs after 24 hours of ingestion measured by prolactin level [19]. The other four ingredients are based on Thai traditional medicine knowledge on alleviation of postpartum elemental imbalance caused by losing stamina, water, and blood from delivery and muscle pain [20–22]. Acute oral toxicity assessment of the tea in Wistar rats revealed a median lethal dose (LD50) of 5,000 mg/kg with no cases of serious side effects [18]. While data from the grey literature found a significant increase in breast milk volume with no serious side effects in the herbal tea group compared to placebo, a randomized controlled trial with standard treatment as active control arm was necessary to provide substantive evidence of the herbal tea efficacy in stimulating breast milk production.

The Wang Nam Yen herbal tea is a promising traditional Thai galactagogue, which might be used as an alternative to the common pharmaceutical galactagogue, domperidone, to support breastfeeding difficulties due to low supply, especially in women that have undergone cesarean deliveries [18]. The objective of this study was to compare the efficacy of Wang Nam Yen herbal tea, domperidone, and a placebo, in augmenting breast milk production in mothers that have undergone Cesarean delivery, in a double-blinded randomized controlled trial.

Methods

Study design

Tea4Milk was a three-armed, double-blinded randomized controlled trial on human milk production conducted in Ubon Ratchathani Province, Thailand at Sunpasitthiprasong Hospital, a regional hospital under the Ministry of Public Health, from February 2017 to September 2017. Participants were recruited after delivery via cesarean section by placing advertisements in four obstetrics wards. All patients provided written informed consent. The study was reviewed and approved by the institutional review board of Sunpasitthiprasong Hospital (No.061/2559). The trial was registered and kept up to date at the Thai Clinical Trial Registry (Registration No. TCTR20170811003).

Participants

Inclusion criteria were women aged 15 to 41 years that had delivered via cesarean section at 28 to 42 weeks gestational age. Participants with contraindications for breastfeeding and/or serious illness affecting mother or infant, such as human immunodeficiency virus infection, postpartum hemorrhage with hypovolemic shock, HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count), eclampsia with respiratory failure, or had a history of allergy to domperidone or ingredients in the herbal tea, or neonates-mother separation before participation were excluded from the study.

Randomization and blinding

Participants were recruited according to inclusion and exclusion criteria through the advertisements at four obstetrics wards by obstetricians and nurses who did not have information on the allocation of participants. Participants were randomly allocated into 3 groups with a 1: 1: 1 ratio by block randomization with a block of three using the table of random numbers for creating randomization ID which was inserted into an opaque envelop to mask clinicians, data collectors, and patients. Randomization ID was assigned as 1) Wang Nam Yen herbal tea and placebo tablet (T group), 2) domperidone tablet and placebo herbal tea (D group), 3) placebo tablet and placebo herbal tea (C group). When 120 randomization IDs were generated, the ID was joined together starting with a randomization ID for participant number 9 (TD009) as the first ID.

Participants and investigators were blinded to the treatment assignment. After generating randomization codes, the research team responsible for blinding created an opaque envelope to seal the randomization codes. The front end of an opaque sealed envelope presented the study name, principal investigator name, site of study, randomization ID, study ID, and specific date to open envelop. There was a document inside the sealed envelope with randomization ID, assigned group, study ID, specific date and time to open envelop, and signature of envelope opener who was not enrollment personnel nor clinician nor data collector. All study interventions were prepacked and sealed in opaque packages, for three consecutive days of postpartum use.

Interventions

Wang Nam Yen herbal tea was manufactured by Wang Nam Yen hospital, a community hospital in Sa Kaeo reputed for Thai traditional herbal medicine. Wang Nam Yen herbal tea was packed in a tea bag designed for each meal. Each Wang Nam Yen herbal tea bag contained 500 mg sappan (Caesalpinia sappan Linn.), 500 mg licorice (Glycyrrhiza glabra Linn.), 500 mg bale fruit (Aegle marmelos L. Corr), 500 mg ginger (Zingiber officinale Roscoe), and 500 mg jewel vine (Derris scandens (Roxb.) Benth). The herbal tea placebo was also prepared as a teabag for each meal, and the placebo tea bag was identical to Wang Nam Yen teabag. The placebo teabag was filled with 2,500 mg pandan (Pandanus amaryllifolius) leaves. All herbal ingredients were from Charoensuk Pharma Supply Co., Ltd. Both herbal teas were prepared by diffusion in 200 mL of warm water for 5 minutes which gave an identical appearance. Interventions were administered orally three times per day after meals. The first administration occurred 12–18 hours following delivery to ensure sufficient time for the evaluation of any postpartum complications that may have occurred. Domperidone was given 10 mg 3 times per day (total dose 30mg daily) which was considered safe and sufficient for increasing breast milk production [23, 24]. The placebo tablet was made of glutinous rice flour with an identical appearance to the domperidone tablet. All participants (T, D, C groups) were administered 200 mL of tea and a tablet after each meal. All groups had similar breastfeeding support for early breastfeeding as early as possible, frequent breastfeeding, correct positioning, and avoiding the use of formula when possible. There was no restriction on early breastfeeding before the first dose of intervention. In case mother-infant separation occurred after randomization, the mothers would continue in the trial similar to other participants except direct breastfeeding would not be possible while the infants would receive standard of care.

T–The Wang Nam Yen herbal tea treatment group received Wang Nam Yen herbal tea and placebo tablet after each meal for three meals per day. This was an intervention arm that was designed to assess the efficacy of Wang Nam Yen herbal tea.

D–The domperidone treatment group received an herbal tea placebo and a 10 mg domperidone tablet after each meal for three meals per day. This was an active control arm that was designed to be a comparator as standard treatment.

C–The placebo control group received both herbal tea placebo and a placebo tablet after each meal for three meals per day. This was a placebo control arm that was designed to be a reference group with no treatment.

Outcome measures

The primary outcome was breast milk volume at 72 hours after delivery. The first breastfeeding was encouraged to be as early as possible and no late than after the first dose of intervention which occurred 12–18 hours following delivery. All participants were encouraged to breastfeed their infants based on Sunpasitthiprasong hospital’s standard of care policy. The breast milk volume was measured with a two-hour interval from the last breastfeeding, using an electronic pump (Spectra S2Plus®, Spectra Baby USA). The electronic pump was applied with help from a trained nurse for 15 minutes during each breast and the total volume of milk was recorded. Breast milk volume was also measured at 24 hours and 48 hours post-delivery. The milk collection was done uniformly for all participants. While some babies might demand hourly feeding, all mothers were notified at 2 hours before each milk collection session which allowed the last breastfeeding before the milk collection. The unit of analysis was the total amount of milk volume in a single 15-minute expression (mL/extraction). The breast milk volume at 24 hours post-delivery was used as the baseline.

Secondary outcomes were observed 72 hours after the delivery period including (1) pregnancy outcomes such as postpartum hemorrhage, endometritis, (2) neonatal outcomes such as neonatal jaundice, respiratory distress, (3) adverse effects including headache, dry mouth, diarrhea, muscle cramps, itching, or allergic reactions assessed every 24 hours by the ward nurses and rechecked by a research assistant, and (4) participant satisfaction during the three days’ postpartum period were also recorded.

Fluid intake and output were recorded daily to assess the maternal fluid volume status. The need for formula milk supplementation was recorded daily due to formula milk supplements might affect both maternal breastmilk production and neonatal breastmilk intake.

Sample size calculation

We used mean and standard deviation of daily breast milk volume (mean treatment = 191.3, mean control = 91.4, standard deviation = 136.1) based on a previous randomized controlled trial by Jantarasaengaram and Sreewapa, 2012 on the effects of domperidone compared to placebo in augmenting lactation following cesarean delivery with 80% power and a 2-sided type I error at 5% [9]. The result required 34.5 samples in each group. Taking into account an expected follow-up loss of 15%, the anticipated sample size of 120 would require a sample size of 40 in each group.

Statistical analysis

The statistical analysis was performed on an intention-to-treat basis using Stata/MP software version 15.0 (StataCorp 2017, College Station, TX). Descriptive statistics were carried out using mean with standard deviation or median with interquartile range when appropriate. Categorical data were presented as counts and percentages and tested for significance with the Chi-square test. Continuous data were assessed for normality and tested for significance with one-way ANOVA with Bonferroni correction for comparison among groups. Statistical significance was defined as p < 0.05 and as p < 0.017 with Bonferroni correction.

Ethics committee approval

The study was approved by the institutional review board of Sunpasitthiprasong Hospital (No.061/2559) and was registered TCTR20170811003 with the Thai Clinical Trial Registry. Written informed consent was obtained from all participants. For participants aged 15–17-year-old, written informed consents were obtained from their parents or guardians.

Results

Participant characteristics

The 1450 women who underwent Cesarean delivery in Sunpasitthiprasong hospital from February 2017 to September 2017 were assessed for eligibility. 303 were excluded due to severe eclampsia, eclampsia, HELLP syndrome, or neonatal separation from mother immediately after birth and 1027 declined participation. A total of 120 mother-infant dyads were enrolled in this study and randomized into three groups, with 40 participants in each (Fig 1). There were six participants whose infants required special care in the neonatal intensive care unit but continued to express their milk via breast pump; three were from the control group, two from the domperidone group, and one from the herbal tea group. All participants completed their prescribed intervention and were analyzed based on their randomization group.

Fig 1. Flow diagram of the clinical trial.

Fig 1

The mean participant age was 28.7 years old with an mean gestational age at delivery of 38.4 weeks. There were no substantial differences between the groups in demographic data including maternal age, highest education, method of payment, and salary per month; or in baseline obstetric data including gestational age, parity, the number of antenatal visits, labor symptoms, the indication of cesarean delivery, birth weight, and sex of the baby (Table 1). Additionally, there were similar rates of immediate postpartum hemorrhage defined by blood loss of more than 1000ml, the average fluid intake and output during the 72 hours postpartum period, and the amount of formula milk required (Table 2).

Table 1. Baseline characteristics of the study participants.

Baseline data Total (n = 120) Herbal tea (n = 40) Domperidone (n = 40) Control (n = 40)
Demographic characteristics
Age (years; mean ± SD) 28.7 ± 5.9 29.2 ± 5.7 28.7 ± 5.9 28.3 ± 6.2
Monthly income (Baht; median, IQR) (n = 99)* 5000 (0, 14000) 5000 (0, 15000) 3000 (0, 11500) 3600 (0, 13000)
Method of payment, n (%)
    Public universal health coverage 67 (55.8%) 20 (50.0%) 27 (67.5%) 20 (50.0%)
    Social welfare 37 (30.8%) 13 (32.5%) 11 (27.5%) 13 (32.5%)
    Government official’s welfare 8 (6.7%) 4 (10.0%) 2 (5.0%) 2 (5.0%)
    Other 8 (6.7%) 3 (7.5%) 0 (0.0%) 5 (12.5%)
Obstetric characteristics
Gestational age (weeks; mean ± SD) 38.4 ± 1.5 38.6 ± 1.0 38.1 ± 2.0 38.7 ± 1.1
Primigravida, n (%) 41 (34.2%) 12 (30.0%) 12 (30.0%) 17 (42.5%)
Antenatal visits more than 3 times, n (%) 58 (48.3%) 19 (47.5%) 19 (47.5%) 20 (50.0%)
Presence of labor symptoms, n (%) 66 (55.0%) 21 (52.5%) 23 (57.5%) 22 (55.0%)
Indication of Cesarean delivery, n (%)
    Cephalopelvic disproportion 48 (40.0%) 15 (37.5%) 15 (37.5%) 18 (45.0%)
    Fetal distress 8 (6.7%) 3 (7.5%) 3 (7.5%) 2 (5.0%)
    Abnormal presentation 9 (7.5%) 3 (7.5%) 4 (10.0%) 2 (5.0%)
    Previous Cesarean delivery 48 (40.0%) 18 (45.0%) 15 (37.5%) 15 (37.5%)
    Others 7 (5.8%) 1 (2.5%) 3 (7.5%) 3 (7.5%)
Experience of breastfeeding, n (%) 64 (53.3%) 24 (60.0%) 21 (52.5%) 19 (47.5%)
Neonatal characteristics
Birthweight (grams; median, IQR) 3067.5 (2737.5, 3337.5) 3147.5 (2736.3, 3475.0) 3055.0 (2743.8, 3302.5) 2975.0 (2715.0, 3307.5)
Sex of baby, n (%)
    Female 60 (50.0%) 20 (50.0%) 18 (45.0%) 22 (55.0%)
    Male 60 (50.0%) 20 (50.0%) 22 (55.0%) 18 (45.0%)

IQR, interquartile range; SD, Standard deviation.

*Data not available for all randomized participants.

Table 2. Puerperal characteristics of the study participants.

Puerperal characteristics Total (n = 120) Herbal tea (n = 40) Domperidone (n = 40) Control (n = 40)
Immediate PPH, n (%) 2 (1.7%) 1 (0.8%) 0 (0.0%) 1 (0.8%)
Average fluid intake per day (ml; mean ± SD) 2566.2 ± 560.6 2525.7 ± 436.9 2602.9 ± 573.6 2569.9 ± 660.4
Average fluid output per day (ml; mean ± SD) 1826.0 ± 542.7 1781.3 ± 452.5 1812.6 ± 583.2 1884.2 ± 590.0
Formula milk required, n (%) (n = 115)*,**,***
    Not required 40 (34.8%) 15 (38.5%) 12 (31.6%) 13 (34.2%)
    Required before 24 hours 22 (19.1%) 6 (15.4%) 9 (23.7%) 7 (18.4%)
    Required before 24 hours and 24–48 hours 22 (19.1%) 7 (18.0%) 8 (21.1%) 7 (18.4%)
    Required before 24 hours, 24–48 hours and 48–72 hours 31 (27.0%) 11 (28.2%) 9 (23.7%) 11 (29.0%)

PPH, postpartum hemorrhage; SD, Standard deviation.

*Data not available for all randomized participants.

**Total percentage is not equal to 100% due to rounding.

***There were no significant differences across the three groups (p = 0.971; Chi-square test).

Primary and secondary outcomes

Breast milk volume per expression at 72 hours postpartum was significantly different among the three groups (p = 0.030). The posthoc Bonferroni correction indicated a significant difference in breast milk volume between Wang Nam Yen herbal tea group at 57.5 ± 50.7 ml and placebo control group at 31.9 ± 27.7 ml (p = 0.007) while there was no difference between Wang Nam Yen herbal tea group at 57.5 ± 50.7 ml and domperidone group at 60.9 ± 70.7 ml (p = 0.806) (Table 3). While there was a significant difference in baseline breast milk volume at 24 hours postpartum among the three groups (p = 0.036), the significant difference between groups was not observed with Bonferroni correction: p = 0.039 for herbal tea and control groups, p = 0.433 for domperidone and control groups, and p = 0.089 for herbal tea and domperidone groups. There was no significant breast milk volume observed among the three groups at 48 hours postpartum (p = 0.256). Fig 2 provided the change in total breastmilk volume per expression at each time point with mean and 95% confidence interval.

Table 3. Primary and secondary outcome measures for maternal complications, neonatal complications, and drug adverse events.

Outcomes Total (n = 120) Herbal tea (n = 40) Domperidone (n = 40) Control (n = 40) p value
Total milk volume per expression
Milk volume at 24 hours (ml; mean ± SD) 5.5 ± 13.9 10.0 ± 21.4 3.8 ± 7.6 2.6 ± 6.2 0.036
     Herbal vs Placebo 0.039
    Domperidone vs Placebo 0.433
    Herbal vs Domperidone 0.089
Milk volume at 48 hours (ml; mean ± SD) 24.5 ± 34.3 28.0 ± 39.8 28.4 ± 40.8 17.2 ± 16.5 0.256
Milk volume at 72 hours (ml; mean ± SD) 50.1 ± 53.9 57.5 ± 50.7 60.9 ± 70.7 31.9 ± 27.7 0.030
    Herbal vs Placebo 0.007
    Domperidone vs Placebo 0.018
    Herbal vs Domperidone 0.806
Maternal complications
Late PPH 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) N/A
Postpartum endometritis 1 (0.8%) 0 (0.0%) 0 (0.0%) 1 (2.5%) 0.365
Neonatal complications
Neonatal jaundice 6 (5.0%) 4 (10.0%) 0 (0.0%) 2 (5.0%) 0.127
NICU admission 6 (5.0%) 1 (2.5%) 2 (5.0%) 3 (7.5%) 0.591
Drug adverse events
Adverse event at 24 hours 2 (1.7%) 1 (2.5%) 1 (2.5%) 0 (0.0%) 0.601
Adverse event at 48 hours 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) N/A
Adverse event at 72 hours 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) N/A

Statistics were analyzed by the Chi-square test for categorical data and the one-way ANOVA test for continuous data. Drug adverse events were one diarrhea in the herbal tea group and one dry mouth in the domperidone group. NICU admissions were either from respiratory distress syndrome or transient tachypnea of the newborn. NICU, neonatal intensive care unit; N/A, not applicable; PPH, postpartum hemorrhage; SD, standard deviation.

Fig 2. Change in human milk volume over time.

Fig 2

Mean and 95% confidence intervals are presented. C, control group; D, domperidone group; T, herbal tea group.

There were no significant differences in maternal or neonate complications among the three groups (Table 3). For maternal complications, one participant in the control group developed postpartum endometritis. For drug adverse events, one participant in the domperidone group reported dry mouth and one participant in the herbal tea group reported diarrhea as an adverse effect during the first 24 hours postpartum and the symptoms persisted for 72 hours postpartum, subsiding only after the end of the trial. Six infants developed jaundice, two in the control and four in the herbal tea group, and six infants required neonatal intensive care unit admission due to respiratory distress syndrome or transient tachypnea of the newborn: one in Wang Nam Yen herbal group, two in the domperidone group, and three in the placebo group.

Based on participant satisfaction outcomes, 64.2% of all the participants liked their breastfeeding experience during the study period, 71.7% liked using galactagogues to increase their milk production and 75.8% would use galactagogues in their subsequent pregnancy, while 18.3% of participants worried about the adverse effects of using galactagogues (Table 4). While not significantly different between the intervention groups, more participants in the control group (32.5%) reported having problems with breastfeeding than participants in the domperidone (20.0%) and herbal tea group (17.5%), and also more participants in herbal tea (62.5%) and domperidone (55.0%) groups agreed to continue the use of galactagogue post-study compared to the control group (35.0%). Of the participating women 68.3% said they would recommend galactagogues to a friend, 75% said they would recommend food to enhance milk production and 78.3% said they would recommend behavior modifications to enhance milk production.

Table 4. Secondary outcome measures for participant satisfaction.

Questions Total (n = 120) Herbal tea (n = 40) Domperidone (n = 40) Control (n = 40) p-value
1. You like your breastfeeding 0.835
    Agree 77 (64.2%) 28 (70.0%) 24 (60.0%) 25 (62.5%)
    Disagree 4 (3.3%) 1 (2.5%) 1 (2.5%) 2 (5.0%)
    Not sure 39 (32.5%) 11 (27.5%) 15 (37.5%) 13 (32.5%)
2. You like to use this galactagogue 0.143
    Agree 86 (71.7%) 29 (72.5%) 28 (70.0%) 29 (72.5%)
    Disagree 3 (2.5%) 0 (0.0%) 0 (0.0%) 3 (7.5%)
    Not sure 31 (25.8%) 11 (27.5%) 12 (13.0%) 8 (20.0%)
3. You have a problem with your breastfeeding 0.200
    Agree 28 (23.3%) 7 (17.5%) 8 (20.0%) 13 (32.5%)
    Disagree 37 (30.8%) 17 (42.5%) 10 (25.0%) 10 (25.0%)
    Not sure 55 (45.8%) 16 (40.0%) 22 (55.0%) 17 (42.5%)
4. You worried about galactagogues adverse effect 0.662
    Agree 22 (18.3%) 5 (12.5%) 7 (17.5%) 10 (25.0%)
    Disagree 56 (46.7%) 19 (47.5%) 20 (50.0%) 17 (42.5%)
    Not sure 42 (35.0%) 16 (40.0%) 13 (32.5%) 13 (32.5%)
5. You decided to continue using galactagogue 0.132
    Agree 61 (50.8%) 25 (62.5%) 22 (55.0%) 14 (35.0%)
    Disagree 10 (8.3%) 3 (7.5%) 2 (5.0%) 5 (12.5%)
    Not sure 49 (40.8%) 12 (30.0%) 16 (40.0%) 21 (52.5%)
6. You will recommend your friend to use this galactagogue 0.171
    Agree 82 (68.3%) 29 (72.5%) 27 (67.5%) 26 (65.0%)
    Disagree 3 (2.5%) 0 (0.0%) 0 (0.0%) 3 (7.5%)
    Not sure 35 (29.2%) 11 (27.5%) 13 (32.5%) 11 (27.5%)
7. You will recommend your friend to eat food enhancing breast milk production 0.791
    Agree 90 (75.0%) 31 (77.5%) 28 (70.0%) 31 (77.5%)
    Disagree 4 (3.3%) 1 (2.5%) 1 (2.5%) 2 (5.0%)
    Not sure 26 (21.7%) 8 (20.0%) 11 (27.5%) 7 (17.5%)
8. You will advise your friend on behavioral ways to continue breastfeeding 0.942
    Agree 94 (78.3%) 32 (80.0%) 30 (75.0%) 32 (80.0%)
    Disagree 5 (4.2%) 2 (5.0%) 2 (5.0%) 1 (2.5%)
    Not sure 21 (17.5%) 6 (15.0%) 8 (20.0%) 7 (17.5%)
9. You will use galactagogue in your subsequent pregnancy 0.412
    Agree 91 (75.8%) 32 (80.0%) 30 (75.0%) 29 (72.5%)
    Disagree 5 (4.2%) 2 (5.0%) 0 (0.0%) 3 (7.5%)
    Not sure 24 (20.0%) 6 (15.0%) 10 (25.0%) 8 (20.0%)

Statistics were analyzed by the Chi-square test.

Discussion

In this study, Wang Nam Yen herbal tea effectively increased breast milk volume production at 72 hours postpartum compared to placebo. There was no significant difference in breast milk volume between Wang Nam Yen herbal tea and the domperidone group. The difference in early augmentation effect at 24 hours postpartum was observed among three groups, but there was no significant difference between any two groups when applying Bonferroni correction. Wang Nam Yen herbal tea and domperidone had no serious side effects on the mothers or infants. One participant reported diarrhea and one participant reported dry mouth as adverse effects from the herbal tea and domperidone group, respectively. The overall satisfaction of using galactagogues was high and most participants would recommend using galactagogues to friends for increasing milk volume production.

Although the study did not measure prolactin levels, the findings demonstrate the efficacy of herbal tea in enhancing milk volume. While the method of collecting milk, using a breast pump to measure milk volume, might affect the study outcome as electronic pumps can disturb normal biological synthesis of breast milk, the results showed the same trend as previous studies of domperidone at 30 mg/day dose in the efficacy to increase breast milk volume [3, 5, 9, 23, 25]. However, breast milk volume at 72 hours postpartum in the domperidone group showed no significant difference from the placebo control group when using Bonferroni correction. This might occur from the disadvantage of Bonferroni’s correction providing smaller-than-required adjusted α which was too conservative, thus often caused false-negative results [26]. While non-breastmilk supplements might affect the amount of breastmilk production and infant breastfeeding behavior [27], there was no significant difference in formula milk supplementation between the groups in this study. The hospital’s standard policy for breastfeeding, including encouraging early breastfeeding, frequent breastfeeding, correct position, and avoiding the use of the formula is important recommendations that should be strictly followed by all mothers before using food, behavior modifications, or galactagogues to increase milk volume production. The findings support the use of galactagogues in addition to behavioral recommendations and food intake to increase breast milk production in mothers with insufficient milk volume following a cesarean delivery [17].

Postpartum endometritis is one of the most common puerperal complications, particularly following cesarean section [28]. While there was a 7% estimated incidence of postpartum endometritis after elective cesarean section [29], no postpartum endometritis in Wang Nam Yen herbal tea group and domperidone group was observed during the trial period. There was no postpartum hemorrhage in Wang Nam Yen herbal tea and the domperidone group. In terms of safety, the side effects of domperidone could include dry mouth, headache, insomnia, abdominal cramps, diarrhea, nausea, and urinary retention [9]. The study found no major side effects, with one report of dry mouth as an adverse effect of domperidone and one report of diarrhea as an adverse effect of the herbal tea, which occurred during the first 24 hours postpartum and continued until the end of the study and after the interventions were stopped the symptoms subsided. Based on the study, there are no safety concerns in using herbal tea during the puerperal period.

There were no significant differences in neonatal outcomes, especially neonatal jaundice, between the intervention and control groups, however, more research may be needed to conclusively support these results [2]. Of 120 infants, six (5%) were admitted to NICU due to respiratory distress syndrome or transient tachypnea of the newborn. The incidence of NICU admission was similar to the previous observational study on term infants of elective cesarean section mothers [30] and slightly lower than term infants of elective repeat cesarean section mothers [31]. No association between the intervention and NICU admission was observed in this study.

As a randomized controlled trial, one of the strengths of this study was by design, as careful randomization and blinding minimized potential confounding factors and biases. This trial was among the first studies to examine the effects of Wang Nam Yen tea compared to domperidone and a placebo. The rationale for factorial design was that domperidone—current medication practice for promoting lactation—is in form of an oral tablet while Wang Nam Yen herbal tea is in form of a teabag needed for infusion of water before use. Thus, the placebo oral tablet and placebo tea were necessary for this study and the two-arm design would not be sufficient. Although the 2x2 design was in our initial research proposal, one arm (herbal tea + domperidone) had to be discarded in response to the comment from the ethics committee. Hence, the potential additive/synergistic effect could not be inferred from our data. Although some participants declined to enroll in the trial before randomization, there were no participants who declined after randomization. Thus, the sample size of this study provided sufficient power and was able to determine the efficacy of Wang Nam Yen herbal tea in increasing breast milk production at 72 hours postpartum as the primary outcome. The results of this study could be applied to pregnant women that underwent cesarean delivery at 37 to 42-week gestational age.

There were several limitations of this study. First, the efficacy of the interventions on other outcomes, such as prolactin level and breast milk volume at 7 days post-administration to confirm hormonal effect and maintenance of augmentation, was not evaluated. Second, while we intended to produce perfect placebo tea with identical external appearance, taste, and aroma. The taste and aroma of placebo tea were difficult to make identical to Wang Nam Yen herbal tea when placebo tea was needed to produce with the ingredient with no galactagogue effect while providing identical external appearance to Wang Nam Yen herbal tea. This might lead to potential bias when some participants might smell or discuss the aroma and taste with other participants although no explicit action was observed in this study. Third, while this study initially intended to include both preterm and term pregnant women, but they were separated from their child before participation which was the exclusion criteria. Hence, none of the mothers with preterm infants met the eligibility criteria and all included participants were term pregnant (Gestational age 37–42 weeks). Thus, the implication of this study could be applied to only mothers with term pregnancies. Fourth, this study did not record data on whether participants in each group were mainly direct breastfeeding or expressing breastmilk for feeding and did not evaluate lactation insufficiency and sucking problems which might affect the breastmilk production. Moreover, the randomization process was conducted with a single size of block randomization which generally might lead to selection bias if the recruiters knew the block size and previous allocation result, thus the next allocation could be predicted. However, this study tried to minimize the potential selection bias by ensuring that the sealed envelope was opened by a person not involve in the recruitment process and was the only person who knew the allocation. Clinicians doing the recruitment and data collectors were not aware of the allocation. Finally, there was a limitation in sample size calculation due to no previous published peer-reviewed evidence on the effect of this herbal tea. Thus, we calculated the sample size using data based on two parallel groups (domperidone and placebo). This might cause a potential underpowering of the study if the true effect of herbal tea was significantly lower than domperidone. On the other hand, if the true effect of herbal tea was significantly higher than domperidone, only sample size overestimation is concerned.

Conclusion

Wang Nam Yen herbal tea, an alternative traditional Thai medicine, was effective in augmenting breast milk production at 72 hours postpartum in mothers following cesarean delivery, and there was no evidence that herbal tea and domperidone differed in terms of augmenting breast milk production.

Supporting information

S1 Checklist

(DOCX)

S1 File. De-identified data set.

(XLSX)

S2 File. Trial study protocol (English).

(DOCX)

S3 File. Trial study protocol (Thai).

(DOCX)

Acknowledgments

The authors thank Mr. Pinit Chinsoi, Abhaibhubejhr College of Thai Traditional Medicine, and Miss Sawitree Ngamwong, Wang Nam Yen hospital, for preparing the herbal and placebo teas, as well as the Faculty of Pharmaceutical Sciences, Ubon Ratchathani University for preparing the Domperidone. We thank Dr. Charnsak Jungmunkong and contributors from Sunpasitthiprasong Hospital for the administrative support of this trial.

Data Availability

All relevant data are within the paper and its Supporting Information files.

Funding Statement

The authors received financial support for the research from the Department of Thai Traditional and Alternative Medicine, Ministry of Public Health, Thailand. The funding source had no involvement in research preparation, study design; collection, analysis, interpretation of data; writing of the report; or in the decision to submit the article for publication.

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Decision Letter 0

Jacqueline J Ho

10 May 2021

PONE-D-21-05057

Efficacy of Wang Nam Yen herbal tea on human milk production: A randomized controlled trial

PLOS ONE

Dear Dr. Pongpirul,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

There are a number of issues pointed out by the reviewers. Reviewer 2 has put in a lot of effort and the comments are very useful and if addressed could add a lot of value to the manuscript. Please address all of these either by editing the submission or explaining why you didn't. One of the most pertinent issues is about the onset of action following ingestion of the two galactagogues in the study. Is anything know about how long it would take for the tea to act and at which stage of lactation it has its main effect? More information would be helpful for the reader to understand whether the time from first ingestion to the time of measurement of milk volume is sufficient and also whether a similar effect might be seen if used later in lactation. 

The issue of inclusion of preterm infants is an important one. It would be helpful to give more information about the preterm infants in the study such as the proportion of preterm infants, very preterm infants and full term infants. This would help readers to judge how much impact the inclusion of preterm infants had on the results. Even with the galactagogue the volume of milk expressed is likely to be lower than in a term infant. 

The reviewers were also confused by your use of the terms Day 4 and 3-days. I assume Day 4 means that infant was 3-days old and not yet 4-days old. i.e 72-48 hours of age? I think it would be useful to just use hours of life or a range of hours such as 72-96 hours. 

It would be useful to the reader if you gave more information in the section on statistical analysis about the use of the Bonferroni correction. With the correction in place what p-value was assumed significant? 

Please submit your revised manuscript by May 22 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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Academic Editor

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**********

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Reviewer #1: This paper reports on a randomised trial of two approaches to breast milk production in women undergoing Caesarean delivery.

There area number of issues with this paper

The design is a three arm trial -the authors need to explain why a 2x2 design was not looked at as this would help see whether the effects of the interventions were additive.

The sample size is not given in sufficient detail to allow someone to reproduce it - especially as the primary comparison would be a 3-way one and the actual effect sizes and sd are not given in the paper.

The allocation method was via sealed envelopes presumably containing the allocation - the investigator is therefore not blind. A block size of three (presumably one per arm per block) gives the opportunity of significant treatment foreknowledge and as such the integrity of the randomisation process is not guaranteed. What tests were performed to ensure envelopes were opened in order, and were those consenting women kept in ignorance of all previous treatment allocations? What were the reasons for not entering and did they differ by next allocation?

72 hours is 3 days post delivery - why are we variously told about 4 day outcomes?

It is statistically incorrect to test at baseline (Table I).

What methods are used when? ANOVA requires iid Normal residuals, Kruskal-Wallis would be used when this isn't the case. Why are they being performed simultaneously? Please explain the tests used at each point and give contrasts and CI wherever possible.

Drug AEs are not assessed similarly between groups and need to be removed or assessed blind to allocation.

Reviewer #2: This study is of good quality with appropriate controls and the authors have followed the guidelines recommended by CONSORT for RCT-studies. The authors have explained that all data relevant to the study have been included in the article and any de-identified data could be shared upon request. The text is quite well written. However, most of the text is written in past tense, and in certain areas, this can be misleading. An example is the first sentence in the introduction section. Perhaps the authors can re-check the whole manuscript to ensure that the tense used is appropriate.

Further clarifications are needed in these sections:

Introduction:

i. To justify the measurement of the outcome at 72 hours, I suggest that the authors provide data for both Wang Nam Yen and domperidone (with appropriate reference to the literature) on how long after ingestion will a galactogenic effect be expected.

ii. A reference is needed for the last few sentences in the 2nd paragraph, and the first sentence of the 3rd paragraph of this section.

iii. Do the authors have data on which component of the Wang Nam Yen is the most active galactagogue? Some discussion on this would be interesting.

Study design:

i. It is not very clear when the participants were recruited. Was it before or after delivery?

ii. Newborn-mother separation is one of the exclusion criteria. Please clarify why were the 6 mothers whose babies were admitted to NICU (thus meeting the exclusion criteria) included in the study.

Participants:

i. Premature infants were included. Their sucking reflex and chances for direct breastfeeding could be impaired. The main stimulant for more breast milk production is direct breastfeeding and expression of breast milk which may not go well with premature infants. How did the authors manage this?

ii. It would be important for readers to know the rationale behind why only mothers who had undergone caesarean section was included in this study.

Randomization and blinding:

i. The authors have taken trouble to ensure each group received similar looking herbal tea bags and tablets. However, it would be important to mention if the intervention tea and the placebo tea will both have the same appearance, taste, and smell. The same goes for the tablets (domperidone vs placebo).

ii. It would be important to mention what was actually used to fill in the placebo tea bags and what was the ingredient used in the placebo tablet, so that readers can be certain that these placebos do not have any galactogenic effect.

iii. Details of how the random sequence was generated and how the allocation concealment was done (which was nicely written in the protocol) should be added into the manuscript.

iv. Other important details available from the protocol such as the availability of similar breastfeeding support to all the groups should also be included into the manuscript.

Intervention:

i. The sentence "Domperidone was administered at 10 mg per dose, as 30 mg of domperidone per day" is rather confusing. Could this be written in as “Domperidone was given 10mg 3 times per day (total dose 30mg daily)."?

Outcomes measures:

i. Clarification is needed on what was the unit of analysis used for the milk volume measurements.

Was the recorded milk volume a single measurement of 'the total amount' obtained from both breasts after a single expression (mls/extraction) OR was it an accumulation of milk volume measured several times a day (mls/day)?

ii. I note that the milk expression is done 2 hours after the baby has last fed. Can the authors clarify how milk collection was done for babies that demand hourly feeding?

iii. Did the mother express her milk herself or did a trained staff help her to do it? This is to see how uniform the milk expression was done.

iv. It would be important to describe how the babies were mainly fed in each group.

• Were the mothers mainly directly breastfeeding or were many of them expressing milk for feeding? It would be useful to know this proportion because frequent effective direct breastfeeding is a powerful stimulator for breast milk production and this could affect the end result.

v. Since supplementing feeding with formula can affect the amount of breastmilk produced, it would be important to mention how many babies were supplemented with milk in each group.

vi. Formula milk supplementation might also affect the baby’s intake and cause less breast emptying, thus a false sense of ‘more breastmilk’. The authors could elaborate on how this is managed.

vii. Table 1 has lots of details such as method of payment, number of antenatal visits and presence of labour symptoms. Perhaps the authors could explain why these information were included. If they do not contribute to breast milk production i.e. potential confounders, perhaps they can omit these details so that the table is less cluttered.

viii. There is a statement "There were no significant differences between the groups in …….72 hours postpartum period or the amount of formula milk required (Table 1)." The amount of formula milk required was not presented in Table 1. I hope the authors will include this in the table.

Results:

i. Mothers with premature babies may have different milk volume production because of physiological reasons and difference in infant sucking abilities. Therefore, the number of mothers with premature babies in each group should be mentioned.

ii. Being able to directly breastfeed a baby can make a difference in milk supply. It would be useful for the authors to provide data (if available) on the proportions of mothers directly breastfeeding in each group.

iii. Do the authors have data on whether the participants have lactation insufficiency, and if so, how many were there in each group? It would be useful for this to be mentioned because lactation insufficient women may produce milk differently from lactation sufficient women. The author’s definition of what they consider lactation insufficient will also be needed if this data is included.

iv. It would be better and clearer if the actual volume and SD (baseline and at 72 hours) were reported. If possible, display in a table. Showing odds ratio of linear regression (95% confidence interval) could be more meaningful than just the p value. Readers will be interested to know the values obtained to support the basis that taking Wang Nam Yen or Domperidone would make a meaningful difference.

v. In addition, the results described narratively in the text and the results displayed in the graph did not seem to match and were confusing. The text stated that the milk volume in Group T was significantly higher than that in Group C, but in the graph, both Group T and Group D were plotted very closed to each other at 72 hours. On the other hand, the text stated that milk volume for Group D and C were not statistically different, but in the graph, they were obviously plotted very far from each other. Further clarification is needed.

vi. The unit of analysis for Figure 2 is needed in the title of the figure. Was it a mean volume of milk per day at 72 hours of life or volume of milk per expression at 72 hours of life, or was it a mean increment of milk volume since baseline?

vii. The authors did mention that milk volume in the domperidone group showed no significant difference from the placebo group after applying Bonferroni correction.

• Please clarify what was meant by the phrase 'too conservative'.

• What confounders was used?

viii. About the adverse effects and Table 2:

• Why was postpartum endometritis highlighted separately in Table 2? If this could be related to the intervention, perhaps it should be discussed in the discussion section as well?

• I am confused with the actual number of adverse events. The text mentioned that 3 mothers suffered adverse events and only mentioned 3 types of adverse events, namely postpartum endometriosis, dry mouth and diarrhoea. However, Table 2 reported 6 types of adverse events (headache, dry mouth, diarrhea, muscle cramps, itching, or allergic reactions) and that there was a total of 6 mothers experiencing them. Could the authors clarify?

• The authors took the trouble to separate out adverse effects occurring at 24h, 48h and 72h in Table 2. Is there a reason to do so? If there is, perhaps details should then be provided as to which adverse effect occurred at which time, and discuss this in the discussion section as well?

ix. About the 6 infants that required NICU admission:

• What was the reason behind the 6 infants requiring ICU admission?

• How were these mother-infant pairs handled when separation did happen after randomization?

• How many were there in each group?

Clear explanation and details would allow readers to know if the admissions were related to intervention and if intention to treat analysis was performed.

x. The manuscript reported some participants experiencing adverse effects which subsided after discontinuing the intervention. Further details are needed to see how were they related to the intervention or could affect the analysis.

• How many other participants in each group did not actually complete the intervention as prescribed, ie did not take it 3 times a day for 3 days?

• At which time point did these participants in each group stopped taking the intervention?

• Was the milk expression continued at each time point for analysis? If yes, was the participants analysed based on their randomized group?

Perhaps these details could be included in the flow diagram or at least in the text of the results.

Discussion

i. The manuscript stated "Although some participants declined to enroll in the trial following randomization, …..". This line needs clarification because it contradicts the flow diagram that showed that participants who declined to enroll were not randomised. If these were participants who had originally consented to take part in the study, but pulled out after randomization, they should be reflected in the study flow diagram as participant drop-outs, hence the final number of participants who were analysed would be less than 40 in each group. The numbers in Table 2 and 3 will also need adjustments. The reasons for dropping out (if any) should be described.

ii. Data on confounding factors to milk production should be stated. This includes:

• when breastfeeding was first initiated (the protocol says that mothers were encouraged to breastfeed within 24 hours, but having her first breastfeed at birth or first breastfeed at 18 hours of life is a big confounder)

• babies were supplemented with formula in each group

• number of infants with sucking problems

• number of mothers with lactation insufficiency

. If they were not available, they could be discussed as limitations of the study.

Reviewer #3: This is an interesting study that seeks to compare the effectiveness of Wang Nam Yen herbal tea vs. domperidone compared to placebo in achieving improved mother's milk production at 72 hrs following delivery. There were 120 participants in the trial who ranged in delivery gestational age between 28-40 weeks, with a mean GA of ~38 wks and a bw of ~3 kg. The treatment was prescribed for 72 hrs with milk volume measurements via pumped milk expression at each 24 hr interval. There were statistically significant differences between Wang Nam Yen herbal tea and placebo, but not between domperidone and placebo or between Wang Nam Yen herbal tea and domperidone. These are important findings that will serve as the basis for future studies. The following are points that should be addressed to strengthen the clarity and strength of the findings:

(1) In the Methods, the placebo tea needs to be delineated and described. How were the participants and investigators blinded given that herbal teas with certain ingredients have particular aromas?

(2) In the Methods, please describe the block size of randomization.

(3) Methods: in the sample size estimate, you mention milk volume at 4 days but this analysis was at 72 hrs. Perhaps you are using data for power that described milk volume differences at 4 days for your sample size calculation. Please rewrite this section.

(4) Methods: it is concerning that women who delivered preterm were analyzed with women who deliver term. I think this is a potential weakness of the study design. Further, in the analyses of neonatal side-effects, the study is not powered to look at preterm neonatal outcomes by treatment. The tea and domperidone may not differ in their safety profile with preterm mothers, but you would need far more mothers enrolled in such a study. I do not think you can extrapolate safety to those born <35wks so easily. You might suggest that this be refined in future studies.

(5) The Discussion needs to be checked for accuracy for scientific English to make it more readable. There are grammatical errors in that section that are not seen in prior sections.

**********

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Reviewer #1: No

Reviewer #2: Yes: Wai Cheng Foong

Reviewer #3: No

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PLoS One. 2022 Jan 31;17(1):e0247637. doi: 10.1371/journal.pone.0247637.r002

Author response to Decision Letter 0


22 May 2021

Dear Editor,

We thank you and the reviewers for the comments and suggestions. We have tried our best to address all of the points raised by you and the reviewers during the past 12 days offered. Please find our point-by-point responses below:

Editor: Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Response: Thank you for your time and consideration. The manuscript was revised to meet PLOS ONE’s publication criteria.

Editor: There are a number of issues pointed out by the reviewers. Reviewer 2 has put in a lot of effort and the comments are very useful and if addressed could add a lot of value to the manuscript. Please address all of these either by editing the submission or explaining why you didn't. One of the most pertinent issues is about the onset of action following ingestion of the two galactagogues in the study. Is anything know about how long it would take for the tea to act and at which stage of lactation it has its main effect? More information would be helpful for the reader to understand whether the time from first ingestion to the time of measurement of milk volume is sufficient and also whether a similar effect might be seen if used later in lactation.

Response: Thank you for your comment. We greatly appreciate Reviewer 2 for the useful pieces of advice. The information about the onset of action following ingesting of the two galactagogues was added in the Introduction section.

Editor: The issue of inclusion of preterm infants is an important one. It would be helpful to give more information about the preterm infants in the study such as the proportion of preterm infants, very preterm infants and full term infants. This would help readers to judge how much impact the inclusion of preterm infants had on the results. Even with the galactagogue the volume of milk expressed is likely to be lower than in a term infant.

Response: We are sorry for the confusing inclusion criteria and discussion. Initially, we intended to include both preterm and term pregnant women, but they were separated from their child before participation which was one of the exclusion criteria. Hence, all included participants were term pregnant (Gestational age 37–42 weeks). To minimize confusion, the inclusion criteria were amended from the first registered protocol. The inclusion criteria in the Methods section were revised and the reason for inclusion criteria amendment was provided in the Discussion section.

Editor: The reviewers were also confused by your use of the terms Day 4 and 3-days. I assume Day 4 means that infant was 3-days old and not yet 4-days old. i.e 72-48 hours of age? I think it would be useful to just use hours of life or a range of hours such as 72-96 hours.

Response: Thank you for pointing out and sorry for the confusion. The terms were revised for clarification throughout the manuscript.

Editor: It would be useful to the reader if you gave more information in the section on statistical analysis about the use of the Bonferroni correction. With the correction in place what p-value was assumed significant?

Response: An additional information on Bonferroni correction was added in the Methods section. P-value was assumed significant at p < 0.017.

Editor: 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

Response: The manuscript was revised to meet PLOS ONE’s style requirements.

Editor: 2. In order to meet our requirements for data accessibility, please provide the following information about the Wang Nam Yen herbal tea prepared by the hospital and the control herbal tea: a) the sources of all ingredients, including the full name of the company or local market; b) the lot numbers of the ingredients; c) the amount of each ingredient contained in one dose of tea

Response: All ingredients for the Wang Nam Yen herbal tea and the control herbal tea were from Charoensuk

Pharma Supply Co.,Ltd. (https://www.cpspharma.co.th/). Unfortunately, no lot number was provided by the company. Each Wang Nam Yen herbal tea bag contained 500 mg sappan (Caesalpinia sappan Linn.), 500 mg licorice (Glycyrrhiza glabra Linn.), 500 mg bale fruit (Aegle marmelos L. Corr), 500 mg ginger (Zingiber officinale Roscoe), and 500 mg jewel vine (Derris scandens (Roxb.) Benth). The herbal tea placebo was also prepared as a teabag for each meal, and the placebo tea bag was identical to Wang Nam Yen teabag. The placebo tea bag was filled with 2,500 mg pandan (Pandanus amaryllifoilus) leaves. The information was provided in the Methods section.

Editor: 3. Please provide additional details regarding participant consent. In the ethics statement in the Methods and online submission information, please ensure that you have specified whether you obtained written informed consent from parents or guardians of 15-17 year old participants.

Response: Additional details on participant consent were added in the Methods and online submission information.

Editor: 4. We note that you have indicated that data from this study are available upon request. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions.

Response: There are no restrictions. De-identified data set was provided as a Supporting Information file.

Reviewer #1: This paper reports on a randomised trial of two approaches to breast milk production in women undergoing Caesarean delivery. There are a number of issues with this paper. The design is a three arm trial -the authors need to explain why a 2x2 design was not looked at as this would help see whether the effects of the interventions were additive.

Response: Thank you for pointing this out. The rationale for factorial design was that domperidone—the current standard medication for promoting lactation—is in form of an oral tablet while Wang Nam Yen herbal tea is in form of a teabag needed for infusion of water before use. Thus, the placebo oral tablet and placebo tea were necessary for this study. The 2x2 design was in our initial research proposal but one arm (herbal tea + domperidone) had to be discarded in response to the comment from the ethics committee. Hence, the potential additive/synergistic effect could not be inferred from our data.

Reviewer #1: The sample size is not given in sufficient detail to allow someone to reproduce it - especially as the primary comparison would be a 3-way one and the actual effect sizes and sd are not given in the paper.

Response: Thank you for your comment. The sample size calculation subheading was revised in the Method section to provide more reproducibility of the study.

Reviewer #1: The allocation method was via sealed envelopes presumably containing the allocation - the investigator is therefore not blind. A block size of three (presumably one per arm per block) gives the opportunity of significant treatment foreknowledge and as such the integrity of the randomisation process is not guaranteed. What tests were performed to ensure envelopes were opened in order and were those consenting women kept in ignorance of all previous treatment allocations? What were the reasons for not entering and did they differ by next allocation?

Response: Thank you for pointing this out. The randomization and blinding subheadings were revised in the Methods section to clarify the process. The allocation method was deliberately ensured that the investigator was blinded. That is, after generating randomization codes, the research team responsible for blinding created an opaque envelope to seal the randomization codes. The front end of an opaque sealed envelope presented the study name, principal investigator name, site of study, randomization ID, study ID, and date which envelope will be opened. There was a document inside the sealed envelope with randomization ID, assigned group, study ID, date and time which envelope will be opened, and signature of envelope opener who are not clinician nor data collector. While a single block size (of three) might cause potential treatment foreknowledge and lead to selection bias, in theory, this trial random allocation was done by a separate research team independent from enrollment personnel, clinician, or data collector to prevent the selection bias.

Reviewer #1: 72 hours is 3 days post delivery - why are we variously told about 4 day outcomes?

Response: We are sorry for the confusion. The terms were revised for clarification throughout the manuscript.

Reviewer #1: It is statistically incorrect to test at baseline (Table I).

Response: Thank you for your comment. The p-values presented in Table 1 were to demonstrate the comparable baseline characteristics of participants across the three groups after the randomization. We believe this statistical information is useful but could be removed as appropriate.

Reviewer #1: What methods are used when? ANOVA requires iid Normal residuals, Kruskal-Wallis would be used when this isn't the case. Why are they being performed simultaneously? Please explain the tests used at each point and give contrasts and CI wherever possible.

Response: Thank you for pointing out a concerning issue. ANOVA and Kruskal-Wallis were not performed simultaneously. ANOVA was used when the continuous variable was normally distributed while Kruskal-Wallis was used when the continuous variable was not normally distributed. The statistical analysis subheading in the Methods section was revised for clarification. Footnote on which statistical test was performed for each variable was added in Table 1.

 

Reviewer #1: Drug AEs are not assessed similarly between groups and need to be removed or assessed blind to allocation.

Response: The allocation concealment was deliberately performed to ensure double-blinded as stated above. Drug AEs were assessed blindly and similar among groups. The Methods section was revised to provide more detail and clarification on randomization and blinding, and outcome measurement.

Reviewer #2: This study is of good quality with appropriate controls and the authors have followed the guidelines recommended by CONSORT for RCT-studies. The authors have explained that all data relevant to the study have been included in the article and any de-identified data could be shared upon request. The text is quite well written. However, most of the text is written in past tense, and in certain areas, this can be misleading. An example is the first sentence in the introduction section. Perhaps the authors can re-check the whole manuscript to ensure that the tense used is appropriate.

Response: Thank you for the compliments. Appropriate use of tense was revised throughout the manuscript.

Reviewer #2: Introduction: i. To justify the measurement of the outcome at 72 hours, I suggest that the authors provide data for both Wang Nam Yen and domperidone (with appropriate reference to the literature) on how long after ingestion will a galactogenic effect be expected.

Response: Thank you for your comment. Additional details on the expected onset of lactogenic effect for both Wang Nam Yen and domperidone were added in the Introduction section.

Reviewer #2: Introduction: ii. A reference is needed for the last few sentences in the 2nd paragraph, and the first sentence of the 3rd paragraph of this section.

Response: Thank you for your comment. The references were added as suggested accordingly.

Reviewer #2: Introduction: iii. Do the authors have data on which component of the Wang Nam Yen is the most active galactagogue? Some discussion on this would be interesting.

Response: Thank you for your comment. Additional information on the most active galactagogue was added in the Introduction section.

Reviewer #2: Study design: i. It is not very clear when the participants were recruited. Was it before or after delivery?

Response: The participants were recruited after delivery by cesarean section. Additional detail was added in the Method section for clarification.

Reviewer #2: Study design: ii. Newborn-mother separation is one of the exclusion criteria. Please clarify why were the 6 mothers whose babies were admitted to NICU (thus meeting the exclusion criteria) included in the study.

Response: Study design: 6 babies were admitted to NICU after participation but did not separate from their mothers whereas the exclusion criteria excluded newborn-mother separation before participation. The Method section was revised to clarify the eligibility criteria.

Reviewer #2: Participants: i. Premature infants were included. Their sucking reflex and chances for direct breastfeeding could be impaired. The main stimulant for more breast milk production is direct breastfeeding and expression of breast milk which may not go well with premature infants. How did the authors manage this?

Response: We are sorry for the confusing inclusion criteria and discussion. Initially, we intended to include both preterm and term pregnant women, but they were separated from their child before participation which was one of the exclusion criteria. Hence, all included participants were term pregnant (Gestational age 37-42 weeks). To minimize confusion, the inclusion criteria were amended from the first registered protocol. The inclusion criteria in the Methods section were revised and the reason for inclusion criteria amendment was provided in the Discussion section.

Reviewer #2: ii. It would be important for readers to know the rationale behind why only mothers who had undergone caesarean section was included in this study.

Response: Women that have undergone cesarean deliveries were selected as the population in this study due to cesarean delivery was a risk factor of inadequate breast milk production. Additional detail was provided in the Introduction section.

Reviewer #2: Randomization and blinding: i. The authors have taken trouble to ensure each group received similar looking herbal tea bags and tablets. However, it would be important to mention if the intervention tea and the placebo tea will both have the same appearance, taste, and smell. The same goes for the tablets (domperidone vs placebo).

Response: Thank you for pointing it out. Additional detail on placebo tea and tablet was provided in the Methods section. While we intended to produce an ideal placebo tea, the taste and aroma of placebo tea were still different from the Wang Nam Yen herbal tea. However, no participants had a chance to take both active and placebo tea simultaneously. An additional discussion on this limitation was provided in the Discussion section.

Reviewer #2: ii. It would be important to mention what was actually used to fill in the placebo tea bags and what was the ingredient used in the placebo tablet, so that readers can be certain that these placebos do not have any galactogenic effect.

Response: The information of ingredients used in placebo tea bags and tablets were added in the Method section accordingly.

Reviewer #2: iii. Details of how the random sequence was generated and how the allocation concealment was done (which was nicely written in the protocol) should be added into the manuscript.

Response: The details of randomization and allocation concealment were added to the Methods section accordingly.

Reviewer #2: iv. Other important details available from the protocol such as the availability of similar breastfeeding support to all the groups should also be included into the manuscript.

Response: The Methods section was revised as suggested accordingly.

Reviewer #2: Intervention: i. The sentence "Domperidone was administered at 10 mg per dose, as 30 mg of domperidone per day" is rather confusing. Could this be written in as “Domperidone was given 10mg 3 times per day (total dose 30mg daily)."?

Response: The sentence was revised as suggested accordingly.

Reviewer #2: Outcomes measures: i. Clarification is needed on what was the unit of analysis used for the milk volume measurements. Was the recorded milk volume a single measurement of 'the total amount' obtained from both breasts after a single expression (mls/extraction) OR was it an accumulation of milk volume measured several times a day (mls/day)?

Response: Thank you for your comment. The unit of analysis was the total amount of milk volume in a single expression (mL/extraction). The Methods section was revised accordingly.

Reviewer #2: Outcomes measures: ii. I note that the milk expression is done 2 hours after the baby has last fed. Can the authors clarify how milk collection was done for babies that demand hourly feeding?

Response: The milk collection was done uniformly for all participants. While some babies might demand hourly feeding, all mothers were notified at 2 hours before each milk collection section which allowed the last breastfeeding prior to the milk collection. The Methods section was revised accordingly.

Reviewer #2: Outcomes measures: iii. Did the mother express her milk herself or did a trained staff help her to do it? This is to see how uniform the milk expression was done.

Response: A trained nurse helped all participants to express their milk. Additional detail was added to the Methods section accordingly.

 

Reviewer #2: Outcomes measures: iv. It would be important to describe how the babies were mainly fed in each group. Were the mothers mainly directly breastfeeding or were many of them expressing milk for feeding? It would be useful to know this proportion because frequent effective direct breastfeeding is a powerful stimulator for breast milk production and this could affect the end result.

Response: Thank you for your comment. Unfortunately, there was no recorded data on the proportion of mothers directly breastfeeding in each group. This was one of the limitation of the study and the Discussion section was revised accordingly.

Reviewer #2: Outcomes measures: v. Since supplementing feeding with formula can affect the amount of breastmilk produced, it would be important to mention how many babies were supplemented with milk in each group.

Response: Thank you for your comment. Information on formula milk supplement measure was added in the Methods and Results section.

Reviewer #2: Outcomes measures: vi. Formula milk supplementation might also affect the baby’s intake and cause less breast emptying, thus a false sense of ‘more breastmilk’. The authors could elaborate on how this is managed.

Response: The need for formula milk supplementation was recorded daily and categorized into 4 groups: no formula milk supplement, required 1-day supplement, required 2 days supplement, and required 3 days supplement. Association between intervention groups and formula milk supplementation was evaluated by Chi-square test. Additional details were added in the Result and the Discussion sections.

Reviewer #2: Outcomes measures: vii. Table 1 has lots of details such as method of payment, number of antenatal visits and presence of labour symptoms. Perhaps the authors could explain why these information were included. If they do not contribute to breast milk production i.e. potential confounders, perhaps they can omit these details so that the table is less cluttered.

Response: Most variables could be potential confounders of breast milk production while some variables were potential confounders for a secondary outcome such as the method of payment, presence of labor symptoms, low socioeconomics status could be potential confounders of postpartum endometriosis. Variable without evidence for potential confounders were omitted from Table 1 as advised.

Reviewer #2: Outcomes measures: viii. There is a statement "There were no significant differences between the groups in …….72 hours postpartum period or the amount of formula milk required (Table 1)." The amount of formula milk required was not presented in Table 1. I hope the authors will include this in the table.

Response: We apologize for the missing information in Table 1. The need for formula milk supplementation was recorded daily and categorized into 4 groups: no formula milk supplement, required 1-day supplement, required 2 days supplement, and required 3 days supplement. The missing information was added in Table 1 accordingly.

Reviewer #2: Results: i. Mothers with premature babies may have different milk volume production because of physiological reasons and difference in infant sucking abilities. Therefore, the number of mothers with premature babies in each group should be mentioned.

Response: As mentioned above, all included participants were term pregnant; no premature infants were included.

Reviewer #2: Results: ii. Being able to directly breastfeed a baby can make a difference in milk supply. It would be useful for the authors to provide data (if available) on the proportions of mothers directly breastfeeding in each group.

Response: Thank you for your comment. Unfortunately, there was no recorded data on the proportion of mothers directly breastfeeding in each group. This was one of the limitation of the study and the Discussion section was revised accordingly.

Reviewer #2: Results: iii. Do the authors have data on whether the participants have lactation insufficiency, and if so, how many were there in each group? It would be useful for this to be mentioned because lactation insufficient women may produce milk differently from lactation sufficient women. The author’s definition of what they consider lactation insufficient will also be needed if this data is included.

Response: Thank you for your comment. We did not evaluate lactation insufficiency in this study. I agree that lactation insufficiency might affect breast milk production. This was a limitation of the study and additional discussion was added in the Discussion section.

Reviewer #2: Results: iv. It would be better and clearer if the actual volume and SD (baseline and at 72 hours) were reported. If possible, display in a table. Showing odds ratio of linear regression (95% confidence interval) could be more meaningful than just the p value. Readers will be interested to know the values obtained to support the basis that taking Wang Nam Yen or Domperidone would make a meaningful difference.

Response: Thank you for your comment. The actual volume and SD of breast milk were added in Table 2.

Reviewer #2: Results: v. In addition, the results described narratively in the text and the results displayed in the graph did not seem to match and were confusing. The text stated that the milk volume in Group T was significantly higher than that in Group C, but in the graph, both Group T and Group D were plotted very closed to each other at 72 hours. On the other hand, the text stated that milk volume for Group D and C were not statistically different, but in the graph, they were obviously plotted very far from each other. Further clarification is needed.

Response: While the statistical test compared mean and SD, the graph plot presented mean with a 95% confidence interval. The distance between the groups in the graph presented a close distance between Group T and Group D while a far distance of Group T or Group D from Group C. The graph plot reflected statistically significant unadjusted results between Group T and Group C, Group D, and Group C. However, when Bonferroni correction was applied, the adjusted result was more valid and might differ from the graph plot.

Reviewer #2: Results: vi. The unit of analysis for Figure 2 is needed in the title of the figure. Was it a mean volume of milk per day at 72 hours of life or volume of milk per expression at 72 hours of life, or was it a mean increment of milk volume since baseline?

Response: Thank you for your comment. The unit of analysis (volume of milk per expression) was added as suggested accordingly.

Reviewer #2: Results: vii. The authors did mention that milk volume in the domperidone group showed no significant difference from the placebo group after applying Bonferroni correction. Please clarify what was meant by the phrase 'too conservative'. What confounders was used?

Response: An additional detail on Bonferroni correction was added in the Methods and Discussion sections. The disadvantage of Bonferroni's correction was small-than-required adjusted α, thus often caused false-negative result. ‘Too conservative’ is equivalent to ‘weak statistical power’. Potential confounders in this study were maternal age, socioeconomic status, method of payment, gestational age, parity status, adequate antenatal care, presence of labor symptom, previous cesarean section, the experience of breastfeeding, neonatal birth weight, postpartum hemorrhage, fluid balance, and formula milk required.

Reviewer #2: Results: viii. About the adverse effects and Table 2: Why was postpartum endometritis highlighted separately in Table 2? If this could be related to the intervention, perhaps it should be discussed in the discussion section as well?

Response: We highlighted postpartum endometritis because this complication was common in cesarean delivery. Information that Wang Nam Yen herbal tea will not significantly increase postpartum endometritis compared to domperidone and placebo could provide more clear safety profile of Wang Nam Yen herbal tea. An additional discussion was added in the Discussion section.

Reviewer #2: Results: I am confused with the actual number of adverse events. The text mentioned that 3 mothers suffered adverse events and only mentioned 3 types of adverse events, namely postpartum endometriosis, dry mouth and diarrhoea. However, Table 2 reported 6 types of adverse events (headache, dry mouth, diarrhea, muscle cramps, itching, or allergic reactions) and that there was a total of 6 mothers experiencing them. Could the authors clarify?

Response: We apologize for the confusing information. There were 3 mothers who suffered adverse events: one with postpartum endometriosis in the control group (we displayed this event in Maternal complication), one with dry mouth in the domperidone group, one with diarrhea in Wang Nam Yen herbal tea group. Table 2 legend “Drug adverse event includes headache, dry mouth, diarrhea, muscle cramps, itching, or allergic reactions.” was intended to mention which symptoms could be considered as drug adverse event, not the actual drug adverse events occurred.

Thus, Table 2 legend was revised to present actual drug adverse events only.

Reviewer #2: Results: The authors took the trouble to separate out adverse effects occurring at 24h, 48h and 72h in Table 2. Is there a reason to do so? If there is, perhaps details should then be provided as to which adverse effect occurred at which time, and discuss this in the discussion section as well?

Response: We recorded adverse events daily for two reasons. First, there was a lack of evidence on when the Wang Nam Yen herbal tea might cause adverse events. Second, we intended to assess how long the adverse events persisted and subsided. Additional details were added to the Results and the Discussion sections.

Reviewer #2: Results: ix. About the 6 infants that required NICU admission: What was the reason behind the 6 infants requiring ICU admission? How were these mother-infant pairs handled when separation did happen after randomization? How many were there in each group? Clear explanation and details would allow readers to know if the admissions were related to intervention and if intention to treat analysis was performed.

Response: The six infants were admitted to NICU due to respiratory distress syndrome or transient tachypnea of the newborn (TTNB) which the authors assumed no association with intervention. When mother-infant separation occurred after randomization, the mothers continued in the trial similar to other participants except direct breastfeeding was not possible while the infants received standard of care. There was 1 infant admitted to NICU in Wang Nam Yen herbal tea group, 2 in the domperidone group, and 3 in the placebo group. Additional details were added in the Methods, Results, and Discussion sections.

Reviewer #2: Results: x. The manuscript reported some participants experiencing adverse effects which subsided after discontinuing the intervention. Further details are needed to see how were they related to the intervention or could affect the analysis. How many other participants in each group did not actually complete the intervention as prescribed, ie did not take it 3 times a day for 3 days? At which time point did these participants in each group stopped taking the intervention? Was the milk expression continued at each time point for analysis? If yes, was the participants analysed based on their randomized group? Perhaps these details could be included in the flow diagram or at least in the text of the results.

Response: We apologize for the confusing information. The phrase “which subsided after discontinuing the intervention” means that the adverse symptoms persisted for 72 hours postpartum and then subsided after the trial end (no intervention received). Thus, all participants were complete the intervention as prescribed and analyzed based on their randomization group. The discussion on adverse events was revised in the Discussion section.

Reviewer #2: Discussion: i. The manuscript stated "Although some participants declined to enroll in the trial following randomization, …..". This line needs clarification because it contradicts the flow diagram that showed that participants who declined to enroll were not randomised. If these were participants who had originally consented to take part in the study, but pulled out after randomization, they should be reflected in the study flow diagram as participant drop-outs, hence the final number of participants who were analysed would be less than 40 in each group. The numbers in Table 2 and 3 will also need adjustments. The reasons for dropping out (if any) should be described.

Response: We apologize for the confusing information. While there were some participants who decline to enroll in the trial before randomization, there were no participants who declined after randomization. Relevant detail in the Discussion section was revised accordingly.

Reviewer #2: Discussion: ii. Data on confounding factors to milk production should be stated. This includes: when breastfeeding was first initiated (the protocol says that mothers were encouraged to breastfeed within 24 hours, but having her first breastfeed at birth or first breastfeed at 18 hours of life is a big confounder), babies were supplemented with formula in each group, number of infants with sucking problems, number of mothers with lactation insufficiency. If they were not available, they could be discussed as limitations of the study.

Response: We apologize for the confusing information. The first breastfeeding was first initiated after the first dose of intervention which occurred 12-18 hours following delivery. Encouragement to breastfeed their infant within 24 hours of delivery was Sanpasitthiprasong hospital's standard of care policy. The Methods section was revised accordingly. Need for formula milk supplementation was recorded daily and categorized into 4 groups: no formula milk supplement, required 1-day supplement, required 2 days supplement, and required 3 days supplement. Association between intervention groups and formula milk supplementation was evaluated by Chi-square test. Additional details were added in the Result and the Discussion sections. We did not evaluate sucking problems in this study. We agree that sucking problem might be a potential confounder of breast milk production. This was a limitation of the study and additional discussion was added in the Discussion section. Likewise, we did not evaluate lactation insufficiency in this study. I agree that lactation insufficiency might affect breast milk production. This was a limitation of the study and additional discussion was added in the Discussion section.

Reviewer #3: This is an interesting study that seeks to compare the effectiveness of Wang Nam Yen herbal tea vs. domperidone compared to placebo in achieving improved mother's milk production at 72 hrs following delivery. There were 120 participants in the trial who ranged in delivery gestational age between 28-40 weeks, with a mean GA of ~38 wks and a bw of ~3 kg. The treatment was prescribed for 72 hrs with milk volume measurements via pumped milk expression at each 24 hr interval. There were statistically significant differences between Wang Nam Yen herbal tea and placebo, but not between domperidone and placebo or between Wang Nam Yen herbal tea and domperidone. These are important findings that will serve as the basis for future studies. The following are points that should be addressed to strengthen the clarity and strength of the findings:

Response: Thank you for your compliments. The manuscript was revised as suggested accordingly.

 

Reviewer #3: (1) In the Methods, the placebo tea needs to be delineated and described. How were the participants and investigators blinded given that herbal teas with certain ingredients have particular aromas?

Response: Thank you for pointing it out. Additional detail on placebo tea and tablet was provided in the Methods section. While we intended to produce an ideal placebo tea, the taste and aroma of placebo tea were still different from the Wang Nam Yen herbal tea. However, no participants had a chance to take both active and placebo tea simultaneously. An additional discussion on this limitation was provided in the Discussion section.

Reviewer #3: (2) In the Methods, please describe the block size of randomization.

Response: Thank you for your comment. The block size of randomization and additional detail were added in the Methods section.

Reviewer #3: (3) Methods: in the sample size estimate, you mention milk volume at 4 days but this analysis was at 72 hrs. Perhaps you are using data for power that described milk volume differences at 4 days for your sample size calculation. Please rewrite this section.

Response: Thank you for pointing out a concerning issue. The sample size calculation subheading was revised in the Method section to provide more detail and reproducibility of the study.

Reviewer #3: (4) Methods: it is concerning that women who delivered preterm were analyzed with women who deliver term. I think this is a potential weakness of the study design. Further, in the analyses of neonatal side-effects, the study is not powered to look at preterm neonatal outcomes by treatment. The tea and domperidone may not differ in their safety profile with preterm mothers, but you would need far more mothers enrolled in such a study. I do not think you can extrapolate safety to those born <35wks so easily. You might suggest that this be refined in future studies.

Response: We are sorry for the confusing inclusion criteria and discussion. Initially, we intended to include both preterm and term pregnant women, but they were separated from their child before participation which was one of the exclusion criteria. Hence, all included participants were term pregnant (Gestational age 37-42 weeks). To minimize confusion, the inclusion criteria were amended from the first registered protocol. The inclusion criteria in the Methods section were revised and the reason for inclusion criteria amendment was provided in the Discussion section.

Reviewer #3: (5) The Discussion needs to be checked for accuracy for scientific English to make it more readable. There are grammatical errors in that section that are not seen in prior sections.

Response: Thank you for your comment. The Discussion section was revised was more readable scientific English.

We hope that our responses are satisfactory. Should there be anything that might improve our work, please kindly inform us. Thank you very much for your kind consideration.

Best Regards,

Assoc. Prof. Dr. Krit Pongpirul, MD, MPH, PhD.

On behalf of the authors

Attachment

Submitted filename: Response to Reviewer Tea4Milk 8.2 (PLoS One) KP clean.docx

Decision Letter 1

Jacqueline J Ho

30 Jun 2021

PONE-D-21-05057R1

Efficacy of Wang Nam Yen herbal tea on human milk production: A randomized controlled trial

PLOS ONE

Dear Dr. Pongpirul,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

I have been through the reviewer responses to your feedback and although they are attached I am highlighting below those areas that need to be addressed. Therefore please respond to these 12 points. If you would like to respond to other points made by the reviewers please do. 

  1. Introduction. Please go through the introduction carefully as some parts are still in the past tense while some parts of the methods are in future tense.

  2.  Sample size calculation. Your response does not really address the concern of the statistical reviewer. It appears that your sample size calculation is based on having 2 parallel groups whereas you have 3. Therefore is the sample size calculation floored? If this is true then it needs to be discussed as a serious limitation in the study

  3. Randomisation Process. The concern is not about who prepared the envelopes, and here you have used an appropriate method, but rather whether the person recruiting patients and deciding whether they met the inclusion criteria know which group the previous patient recruited was allocated to? If they did then they may foreknowledge of what the next allocation will be and this could affect their decision whether to recruit a particular patient. I suggest you describe the recruitment process from this angle? Was recruitment always done by the same clinician? Would they know the previous allocation? Do you need to acknowledge a limitation here?

  4. Participants. Inclusion of preterm infants. It is still not clear whether or not you intended to include preterm infants. In the methods it appears that they were not included (you have deleted them) but in the discussion it appears that you intended to include them but indeed there were no preterm infants that met your inclusion criteria. Please clarify. My suggestion is that you leave preterm infants in as an inclusion criteria, but state that none met the inclusion criteria. The discussion could then be about the implications of not having preterms in the study

  5. Table 1. As suggested by the statistical reviewer please remove the statistics. In my view you don’t need all the columns – only the column with totals. However some of the data on the table are not actually baseline characteristics. For example formula use before 24, at 24-48 and 48-72 hours. Consider whether these need to go into a separate table. To avoid confusion please also change the data collection times to hours.

  6. Statistical tests. The wording still suggests that both tests (ANOVA and Kruskal Wallace) were used simultaneously. Is it due to the word ‘’and’’. Don’t forget to take the footnote out of Table 1 since you will be taking out the statistical data.

  7. Adverse drug effects. It would be helpful to give more information about how adverse drug

  8. reactions were sought. Specifically were the participants asked directly about each of the outcomes listed or were they asked a broad question such as do you have any other symptoms. It may be that this is what was listed is just the authors definitions of what would be considered an adverse event. This would clear up the confusion about Table 2. Adverse effects are still not clear from the table. While I understand that you collected adverse events at each 24-hour period the table does suggest there were 3 adverse events in the tea group and 3 in the domperidone group - one presenting in each 24-hour period. This needs to be made clearer.   

  9. Methods: I think more detail is needed on the feeding policy of babies after caesarean birth. I note from the methods that the first feeding appears to be at 12-18 hours after birth. Is this correct and if so is this the standard procedure? Most hospitals would start skin to skin and allow breastfeeding either in the operation theatre delivery is under spinal or epidural or as soon as the mother was awake when given general anaesthesia. So for many readers it is unclear whether the baby had been allowed to breastfeed prior to recruitment. Were babies allowed to feed prior to recruitment at 12-18 hours and if so what feeding was allowed? Were mothers allowed to express milk before 12-18 hours?

  10. Results: Adding a line into the text to indicate that 'All participants completed their prescribed intervention and were analysed based on their randomization group' will help to reduce future queries on drop-outs. (If this is true)

  11. Results: Reviewer 2 has a concern about statistical test results: The authors mention that going by the p values, there is no significant difference between the domperidone and placebo group. However, just looking at the p values does not make logical sense to me. If Wang Nam Yen Herbal tea was better than placebo and Wang Nam Yen Herbal tea is equal to Domperidone, therefore logically Domperidone should be better than placebo. I think it is very misleading to portray that domperidone is similar to placebo as it currently stands. What is the reason for this? Readers could interpret this as selective reporting bias.

  12. There are still many grammatical issues right through the manuscript. Reviewer 2 has pointed out a few. Please do get it read by someone with a good grasp of English.

Please submit your revised manuscript by Aug 14 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

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If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

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We look forward to receiving your revised manuscript.

Kind regards,

Jacqueline J. Ho, MB.ChB, MMedSc(ClinEpid), FRCP, FRCPCH, FRCPI

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: No

Reviewer #2: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: I Don't Know

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: No

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Thank you for your previous responses. I think there are some issues not addressed.

As testing at baseline is not correct (there is a substantial literature) please remove as previously requested.

Randomisation: please explain how it was not possible for the envelope to be opened before the front was filled in. Also, with the block size as given, if two allocations are known so is the third and hence there is treatment foreknowledge. Please see the extensive literature on this subject notably by Schultz and Grimes, and the quantification of these biases of Hills, Gray & Wheatley.

Please give more detail no the sample size calculation - the data given is for two groups without Bonferroni correction but there are three here. What was the justification for using the same SD, and presumably effect size.

Are 95% CI for the mean or the variable in the figures?

Reviewer #2: The manuscript is much improved. However, there remains a few areas that still need to be addressed or clarified.

1. Reviewer #2: Outcomes measures: ii. I note that the milk expression is done 2 hours after the baby has last fed. Can the authors clarify how milk collection was done for babies that demand hourly feeding?

Response: The milk collection was done uniformly for all participants. While some babies might demand hourly feeding, all mothers were notified at 2 hours before each milk collection section which allowed the last breastfeeding prior to the milk collection. The Methods section was revised accordingly.

Response to author's response: Thank you for the explanation. However, what the authors have described would mean that the baby must not be breastfed 2 hours before the milk measurement. Therefore, if baby was hungry and crying for feeds during these 2 hours, was he given formula or expressed milk to ease his hunger?

2. Reviewer #2: Outcomes measures: vii. Table 1 has lots of details such as method of payment, number of antenatal visits and presence of labour symptoms. Perhaps the authors could explain why these information were included. If they do not contribute to breast milk production i.e. potential confounders, perhaps they can omit these details so that the table is less cluttered.

Response: Most variables could be potential confounders of breast milk production while some variables were potential confounders for a secondary outcome such as the method of payment, presence of labor symptoms, low socioeconomics status could be potential confounders of postpartum endometriosis. Variable without evidence for potential confounders were omitted from Table 1 as advised.

Response to author's response:

• I still see that method of payment, presence of labor symptoms, low socioeconomics status are still listed in Table 1. The authors explained that these could be confounding factors for the secondary outcomes. However, I still cannot understand how mode of payment and low socioeconomics status can affect any of the secondary outcomes. For example, how can mode of payment cause drug adverse events, jaundice or NICU admission? Could authors also explain how “low socioeconomic group’ causes endometriosis’ and include this somewhere in the text? I cannot understand the scientific rationale behind this.

• On the other hand, ‘highest education level’ was taken out from the table. To me, this is an important confounding factor which should remain in the table-– mothers with higher levels of education could have a better understanding of breastfeeding/ breastfeeding techniques, nutrition etc, thus potentially impact on the amount of breastmilk produced.

3. Reviewer #2: Results: I am confused with the actual number of adverse events. The text mentioned that 3 mothers suffered adverse events and only mentioned 3 types of adverse events, namely postpartum endometriosis, dry mouth and diarrhoea. However, Table 2 reported 6 types of adverse events (headache, dry mouth, diarrhea, muscle cramps, itching, or allergic reactions) and that there was a total of 6 mothers experiencing them. Could the authors clarify?

Response: We apologize for the confusing information. There were 3 mothers who suffered adverse events: one with postpartum endometriosis in the control group (we displayed this event in Maternal complication), one with dry mouth in the domperidone group, one with diarrhea in Wang Nam Yen herbal tea group. Table 2 legend “Drug adverse event includes headache, dry mouth, diarrhea, muscle cramps, itching, or allergic reactions.” was intended to mention which symptoms could be considered as drug adverse event, not the actual drug adverse events occurred.

Thus, Table 2 legend was revised to present actual drug adverse events only.

Response to author's response: Thank you for the explanation

• However, I think the title for Table 2 is still confusing. Suggest to simplify it to just " Table 2: Primary and secondary outcomes"

• I still find there is too much unnecessary details in the table which makes it very difficult to understand and creates a lot of confusion. Would the authors consider only putting the important ones there, and have the rest written in the text?

For example, there was only one mother that had one adverse event – could all of them be grouped under ‘Adverse events’ and then the details that 2 of them occurred at 24 hours which lasted for 72 hours be written in the text instead of having all these information in the table? The way the data is displayed in the table will make the reader think that one participant had an adverse effect occurring at the 24th hour, another at the 48th hour, and another at the 72nd hour, etc.

In addition, presenting the data on Drug adverse events as a row immediately after ‘neonatal complications’ adds to the confusion because these events only happened to mothers and not the babies. Suggest to move the row on adverse events under ‘maternal complications’

• Abbreviation denotated in the legend is difficult to understand. Suggest to follow the style in PLOS. In addition, do you need to include so much detail in the legend? Won’t it be better for the details to be described in the text instead?

4. Reviewer #2: Discussion: ii. Data on confounding factors to milk production should be stated. This includes: when breastfeeding was first initiated (the protocol says that mothers were encouraged to breastfeed within 24 hours, but having her first breastfeed at birth or first breastfeed at 18 hours of life is a big confounder), babies were supplemented with formula in each group, number of infants with sucking problems, number of mothers with lactation insufficiency. If they were not available, they could be discussed as limitations of the study.

Response: We apologize for the confusing information. The first breastfeeding was first initiated after the first dose of intervention which occurred 12-18 hours following delivery. Encouragement to breastfeed their infant within 24 hours of delivery was Sanpasitthiprasong hospital's standard of care policy. The Methods section was revised accordingly. Need for formula milk supplementation was recorded daily and categorized into 4 groups: no formula milk supplement, required 1-day supplement, required 2 days supplement, and required 3 days supplement. Association between intervention groups and formula milk supplementation was evaluated by Chi-square test. Additional details were added in the Result and the Discussion sections. We did not evaluate sucking problems in this study. We agree that sucking problem might be a potential confounder of breast milk production. This was a limitation of the study and additional discussion was added in the Discussion section. Likewise, we did not evaluate lactation insufficiency in this study. I agree that lactation insufficiency might affect breast milk production. This was a limitation of the study and additional discussion was added in the Discussion section.

Response to author's response: Confounders like infant sucking problems, lactation insufficiency have now been adequately addressed. However, I am still confused with the first sentence in your response above " The first breastfeeding was first initiated after the first dose of intervention which occurred 12-18 hours following delivery." Do you mean that the babies were not fed for 12 to 18 hours after birth and had to wait until the mothers were administered the intervention before they could have their first feed? If not, I still think it is important to provide information on when the babies were first put to breast (mean time to first breastfeeding after delivery) or put this as a limitation if the information is not available.

5. Responses to revised manuscript: There are still areas where typo errors/ grammatical errors are found. Eg:

• Method section

Participants were recruited after delivered (‘delivery’ not ‘delivered’) via cesarean section by placing advertisements in four obstetrics wards.

• Discussion section.

Second, while we intended … This might lead to potential bias when some participants might smell or discuss (missing ‘the’) aroma and taste with other participants even no explicit action was observed in this study.

6. Reviewer #2: Results: vii. The authors did mention that milk volume in the domperidone group showed no significant difference from the placebo group after applying Bonferroni correction. Please clarify what was meant by the phrase 'too conservative'. What confounders was used?

Response: An additional detail on Bonferroni correction was added in the Methods and Discussion sections. The disadvantage of Bonferroni's correction was small-than-required adjusted α, thus often caused false-negative result. ‘Too conservative’ is equivalent to ‘weak statistical power’. Potential confounders in this study were maternal age, socioeconomic status, method of payment, gestational age, parity status, adequate antenatal care, presence of labor symptom, previous cesarean section, the experience of breastfeeding, neonatal birth weight, postpartum hemorrhage, fluid balance, and formula milk required.

Response to author's response: The authors mention that going by the p values, there is no significant difference between the domperidone and placebo group. However, just looking at the p values does not make logical sense to me. If Wang Nam Yen Herbal tea was better than placebo and Wang Nam Yen Herbal tea is equal to Domperidone, therefore logically Domperidone should be better than placebo. I think it is very misleading to portray that domperidone is similar to placebo as it currently stands.

7. Reviewer #2: Results: x. The manuscript reported some participants experiencing adverse effects which subsided after discontinuing the intervention. Further details are needed to see how were they related to the intervention or could affect the analysis. How many other participants in each group did not actually complete the intervention as prescribed, ie did not take it 3 times a day for 3 days? At which time point did these participants in each group stopped taking the intervention? Was the milk expression continued at each time point for analysis? If yes, was the participants analysed based on their randomized group? Perhaps these details could be included in the flow diagram or at least in the text of the results.

Response: We apologize for the confusing information. The phrase “which subsided after discontinuing the intervention” means that the adverse symptoms persisted for 72 hours postpartum and then subsided after the trial end (no intervention received). Thus, all participants were complete the intervention as prescribed and analyzed based on their randomization group. The discussion on adverse events was revised in the Discussion section.

Response to author's response: Adding a line into the text to indicate that 'All participants completed their prescribed intervention and were analysed based on their randomization group' will help to reduce future queries on drop-outs.

**********

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Reviewer #1: No

Reviewer #2: Yes: Wai Cheng Foong

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PLoS One. 2022 Jan 31;17(1):e0247637. doi: 10.1371/journal.pone.0247637.r004

Author response to Decision Letter 1


19 Aug 2021

Dear Editor,

We thank you and the reviewers for the comments and suggestions. We have tried our best to address and clarify all of the 12 concerning points raised by you and the reviewers. Please find our point-by-point responses below:

Editor: I have been through the reviewer responses to your feedback and although they are attached I am highlighting below those areas that need to be addressed. Therefore please respond to these 12 points. If you would like to respond to other points made by the reviewers please do.

Response: Thank you for your time and consideration. We sincerely appreciate you and Reviewer 2 for the invaluable advice. The manuscript was revised to address all concerning issues and to meet PLOS ONE’s publication criteria.

Editor: 1. Introduction. Please go through the introduction carefully as some parts are still in the past tense while some parts of the methods are in future tense.

Response: Sorry for improper English grammar use. The introduction and methods sections were thoroughly revised to provide proper English grammar use.

Editor: 2. Sample size calculation. Your response does not really address the concern of the statistical reviewer. It appears that your sample size calculation is based on having 2 parallel groups whereas you have 3. Therefore is the sample size calculation floored? If this is true then it needs to be discussed as a serious limitation in the study

Response: There was a limitation in sample size calculation due to no published peer-reviewed evidence on the effect of this herbal tea. Thus, we calculated the sample size using data based on two parallel groups (domperidone and placebo). This might cause a potential problem due to underpower of the study if the true effect of herbal tea was significantly lower than that of domperidone. On the other hand, if the true effect of herbal tea was significantly higher than that of domperidone, there would be only overestimation of sample size. The Discussion section was revised to address this limitation.

Editor: 3. Randomisation Process. The concern is not about who prepared the envelopes, and here you have used an appropriate method, but rather whether the person recruiting patients and deciding whether they met the inclusion criteria know which group the previous patient recruited was allocated to? If they did then they may foreknowledge of what the next allocation will be and this could affect their decision whether to recruit a particular patient. I suggest you describe the recruitment process from this angle? Was recruitment always done by the same clinician? Would they know the previous allocation? Do you need to acknowledge a limitation here?

Response: Thank you for pointing out this important concern and sorry for the unclear message. The allocation seal envelop opener was the only person who knows which group the patient belongs due to the opener was not involve with the recruitment process, was not the clinician, and was not the data collector as described in the manuscript. This process was done to minimize the potential selection bias from a single block size. The Randomization and blinding section was revised as suggested whereas the limitation of single block size randomization and the method to minimize the potential selection bias was provided in the Discussion section.

Editor: 4. Participants. Inclusion of preterm infants. It is still not clear whether or not you intended to include preterm infants. In the methods it appears that they were not included (you have deleted them) but in the discussion it appears that you intended to include them but indeed there were no preterm infants that met your inclusion criteria. Please clarify. My suggestion is that you leave preterm infants in as an inclusion criteria, but state that none met the inclusion criteria. The discussion could then be about the implications of not having preterms in the study

Response: Sorry for the unclear messages. Yes, we intended to include the preterm infants but ended up with no preterm infants included in the study due to none was met the inclusion criteria as you understood. The Participants and Discussion sections were revised accordingly.

Editor: 5. Table 1. As suggested by the statistical reviewer please remove the statistics. In my view you don’t need all the columns – only the column with totals. However some of the data on the table are not actually baseline characteristics. For example formula use before 24, at 24-48 and 48-72 hours. Consider whether these need to go into a separate table. To avoid confusion please also change the data collection times to hours.

Response: Thank you for your suggestion. The statistics portion of Table 1 was removed as suggested. The data, which were not actually baseline characteristics, were separated to Table 2. The data collection unit was changed from times to hours as advised.

Editor: 6. Statistical tests. The wording still suggests that both tests (ANOVA and Kruskal Wallace) were used simultaneously. Is it due to the word ‘’and’’. Don’t forget to take the footnote out of Table 1 since you will be taking out the statistical data.

Response: Since the Kruskal Wallis test was used for continuous data with non-normal distribution, the Kruskal Wallis test was applied for monthly income and neonatal birthweight in Table 1. After removing the statistics in Table 1 as suggested, the Kruskal Wallis test was not used in remaining statistical tests. Thus, the Statistical analysis section was revised to remove the Kruskal Wallis test accordingly.

Editor: 7 & 8. Adverse drug effects. It would be helpful to give more information about how adverse drug reactions were sought. Specifically were the participants asked directly about each of the outcomes listed or were they asked a broad question such as do you have any other symptoms. It may be that this is what was listed is just the authors definitions of what would be considered an adverse event. This would clear up the confusion about Table 2. Adverse effects are still not clear from the table. While I understand that you collected adverse events at each 24-hour period the table does suggest there were 3 adverse events in the tea group and 3 in the domperidone group - one presenting in each 24-hour period. This needs to be made clearer.

Response: Each of the drug adverse events including headache, dry mouth, diarrhea, muscle cramps, itching, or allergic reactions was asked one by one. The previous data in Table 2 were intended to suggest that one adverse event (diarrhea) in tea group persisted for three days and one adverse event (dry mouth) in domperidone group persisted for three days. We agree that the previous data in Table was not clear enough. Hence, the new Table 3 (previously Table 2) was revised to deliver clear message of adverse event by report the adverse event only at the time of onset to reduce misunderstanding.

Editor: 9. Methods: I think more detail is needed on the feeding policy of babies after caesarean birth. I note from the methods that the first feeding appears to be at 12-18 hours after birth. Is this correct and if so is this the standard procedure? Most hospitals would start skin to skin and allow breastfeeding either in the operation theatre delivery is under spinal or epidural or as soon as the mother was awake when given general anaesthesia. So for many readers it is unclear whether the baby had been allowed to breastfeed prior to recruitment. Were babies allowed to feed prior to recruitment at 12-18 hours and if so what feeding was allowed? Were mothers allowed to express milk before 12-18 hours?

Response: Sorry for miscommunication with the previous information. Both group has similar breastfeeding support for early breastfeeding, frequent breast feeding, correct positioning, and avoiding the use of formula when possible. The standard of care at the Sunpasithiprasong Hospital for early breastfeeding is as early as possible. However, the actual time in some cases might be as late as 24 hours after birth which might not match with the first intervention timepoint in this study. Thus, we promote early breastfeeding as possible and ensure that at least the first breastfeeding was done after the first dose of intervention which occurred 12-18 hours after birth but earlier breastfeeding would be better and there was no restriction on early breastfeeding prior 12-18 hours after birth. The Methods section was revised to clarify the miscommunication.

Editor: 10. Results: Adding a line into the text to indicate that 'All participants completed their prescribed intervention and were analysed based on their randomization group' will help to reduce future queries on drop-outs. (If this is true)

Response: Thank you for your suggestion. This statement was true and was added in the Statistical analysis section accordingly.

Editor: 11. Results: Reviewer 2 has a concern about statistical test results: The authors mention that going by the p values, there is no significant difference between the domperidone and placebo group. However, just looking at the p values does not make logical sense to me. If Wang Nam Yen Herbal tea was better than placebo and Wang Nam Yen Herbal tea is equal to Domperidone, therefore logically Domperidone should be better than placebo. I think it is very misleading to portray that domperidone is similar to placebo as it currently stands. What is the reason for this? Readers could interpret this as selective reporting bias.

Response: Thank you for pointing out this important concern. There was no particular reason for reporting that the domperidone is similar to placebo as the authors also believed that this similarity was due to use of Bonferroni correction, which was conservative method of post-hoc correction, thus we discussed this specific issue on Discussion section. However, the interpretation of result was impartial and followed the proper interpretation of Bonferroni correction. On the other hand, we concerned that if we did not interpret the data as the results presented, that might be another type of selective reporting bias. To be more specific in this study, the effect of herbal vs placebo was slightly higher than effect of domperidone vs placebo, thus it was not uncommon that while herbal vs domperidone was similar, the result of herbal vs placebo and result of domperidone vs placebo might not be the same when the statistical tests applied. This should not be interpreted that the domperidone was similar to placebo since the primary outcome of this study was to study the efficacy of herbal tea vs domperidone and herbal tea vs placebo. The manuscript text about the breast milk per expression at 72 hours postpartum for the domperidone group and the placebo group was deleted to reduce the confusion and to reflect the primary outcome while the result was still provided in the Table 3 to avoid the selective reporting bias.

 

Editor: 12. There are still many grammatical issues right through the manuscript. Reviewer 2 has pointed out a few. Please do get it read by someone with a good grasp of English.

Response: Thank you for your suggestion. The grammatical issues were revised throughout the manuscript accordingly.

We hope that our responses are satisfactory. Should there be anything that might improve our work, please kindly inform us. Thank you very much for your kind consideration.

Best Regards,

Assoc. Prof. Dr. Krit Pongpirul, MD, MPH, PhD.

On behalf of the authors

Attachment

Submitted filename: Response to Reviewer Tea4Milk 2 KP clean.docx

Decision Letter 2

Jacqueline J Ho

3 Sep 2021

PONE-D-21-05057R2

Efficacy of Wang Nam Yen herbal tea on human milk production: A randomized controlled trial

PLOS ONE

Dear Dr. Pongpirul,

Thank you for submitting your manuscript to PLOS ONE. Unfortunately there are still one or two issues that need to be addressed before the manuscript fully meets PLOS ONE’s publication criteria. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

You will find your latest version of the manuscript attached with your track changes shown. I have made quite a number of suggestions where the grammar could be improved as well as a couple of suggestions where further information might be needed. 

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Jacqueline J. Ho, MB.ChB, MMedSc(ClinEpid), FRCP, FRCPCH, FRCPI

Academic Editor

PLOS ONE

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Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Attachment

Submitted filename: Manuscript Tea4Milk 8.3 (PLOS ONE) TN KP editor edits.docx

PLoS One. 2022 Jan 31;17(1):e0247637. doi: 10.1371/journal.pone.0247637.r006

Author response to Decision Letter 2


10 Sep 2021

Dear Editor,

Words cannot express how thankful we are with your impressively careful edits of our manuscript. We followed our advise on the language edits and provided responses to your queries.

We hope that the revised version of our manuscript is satisfactory. Should there be anything that might improve our work, please kindly inform us. Thank you very much for your kind consideration.

Best Regards,

Assoc. Prof. Dr. Krit Pongpirul, MD, MPH, PhD.

On behalf of the authors

Decision Letter 3

Jacqueline J Ho

20 Sep 2021

PONE-D-21-05057R3Efficacy of Wang Nam Yen herbal tea on human milk production: A randomized controlled trialPLOS ONE

Dear Dr. Pongpirul,

Thank you for submitting your manuscript to PLOS ONE. The submission looks much better and is very close to meeting the requirements for PLOS ONE.  There is just one small issue and that is that there is no description on how adverse effects were collected. We do not know how the participant was asked. For example was the participant asked whether they experienced any adverse effects and if so what were they or was the participant asked specifically about whether they had experienced any of the listed adverse effects. If so where did this list come from? Were these know adverse effects of the intervention? If they were asked specifically about these was there also a question on whether they experienced any unexpected adverse effects. If they were asked about unexpected adverse effects and reported these what were they?   

Please submit your revised manuscript by Nov 04 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to this point. You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Jacqueline J. Ho, MB.ChB, MMedSc(ClinEpid), FRCP, FRCPCH, FRCPI

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2022 Jan 31;17(1):e0247637. doi: 10.1371/journal.pone.0247637.r008

Author response to Decision Letter 3


22 Sep 2021

Editor: There is just one small issue and that is that there is no description on how adverse effects were collected. We do not know how the participant was asked. For example was the participant asked whether they experienced any adverse effects and if so what were they or was the participant asked specifically about whether they had experienced any of the listed adverse effects. If so where did this list come from? Were these know adverse effects of the intervention? If they were asked specifically about these was there also a question on whether they experienced any unexpected adverse effects. If they were asked about unexpected adverse effects and reported these what were they?

Response: Many thanks for the thorough assessment and the important comment. Each participant was asked for the presence of each of the potential adverse drug reactions to the study drugs, along with the post-partum clinical parameters, by the study nurse as described in the manuscript. Based on the findings from previous unpublished quasi-experimental study comparing the herbal tea (study group) with a pandan leave tea (control group) (Ref 18), participant in the study group reported no adverse drug reactions whereas one participant in the control group who had consumed the pandan leave tea for two days reported a 5-minute headache episode at 2-3 minutes after consuming the herbal tea on day 3 and day 4. As ‘headache’ could be a general subjective feeling after consuming tea of any kind, we merged the headache in the initial list of potential adverse drug reactions, along with that of domperidone as presented in the Methods section. The participants were also asked about any other symptoms that they experienced after consuming the study drugs that were not in the initial list. In fact, some participants reported a mild degree of abdominal discomfort and sleep difficulty but both symptoms were assessed by the investigators as not related to the study drugs.

Attachment

Submitted filename: responses.docx

Decision Letter 4

Jacqueline J Ho

3 Dec 2021

Efficacy of Wang Nam Yen herbal tea on human milk production: A randomized controlled trial

PONE-D-21-05057R4

Dear Dr. Pongpirul,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Jacqueline J. Ho, MB.ChB, MMedSc(ClinEpid), FRCP, FRCPCH, FRCPI

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

I have accepted your description about the collection of adverse events. Although the description in the manuscript of how the adverse events were identified could be clearer, (e.g. whether participants were asked specifically whether they experienced each of the listed adverse events or whether they were asked just to describe any adverse events that noticed), I have agreed to accept it as is. 

Reviewers' comments:

Acceptance letter

Jacqueline J Ho

19 Jan 2022

PONE-D-21-05057R4

  Efficacy of Wang Nam Yen herbal tea on human milk production: A randomized controlled trial

Dear Dr. Pongpirul:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Professor Jacqueline J. Ho

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Checklist

    (DOCX)

    S1 File. De-identified data set.

    (XLSX)

    S2 File. Trial study protocol (English).

    (DOCX)

    S3 File. Trial study protocol (Thai).

    (DOCX)

    Attachment

    Submitted filename: Response to Reviewer Tea4Milk 8.2 (PLoS One) KP clean.docx

    Attachment

    Submitted filename: Response to Reviewer Tea4Milk 2 KP clean.docx

    Attachment

    Submitted filename: Manuscript Tea4Milk 8.3 (PLOS ONE) TN KP editor edits.docx

    Attachment

    Submitted filename: responses.docx

    Data Availability Statement

    All relevant data are within the paper and its Supporting Information files.


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