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PLOS ONE logoLink to PLOS ONE
. 2021 Jul 1;16(7):e0254049. doi: 10.1371/journal.pone.0254049

Use and experiences of galactagogues while breastfeeding among Australian women

Grace M McBride 1,2,3, Robyn Stevenson 1, Gabriella Zizzo 1, Alice R Rumbold 1,2,3, Lisa H Amir 4,5, Amy K Keir 1,2,3, Luke E Grzeskowiak 1,2,3,6,7,*
Editor: Jane Anne Scott8
PMCID: PMC8248610  PMID: 34197558

Abstract

Background

Galactagogues are substances thought to increase breast milk production, however evidence to support their efficacy and safety remain limited. We undertook a survey among Australian women to examine patterns of use of galactagogues and perceptions regarding their safety and effectiveness.

Methods

An online, cross-sectional survey was distributed between September and December 2019 via national breastfeeding and preterm birth support organisations, and networks of several research institutions in Australia. Women were eligible to participate if they lived in Australia and were currently/previously breastfeeding. The survey included questions about galactagogue use (including duration and timing), side effects and perceived effectiveness (on a scale of 1 [Not at all effective] to 5 [Extremely effective]).

Results

Among 1876 respondents, 1120 (60%) reported using one or more galactagogues. Women were 31.5 ± 4.8 years (mean ± standard deviation) at their most recent birth. Sixty-five percent of women were currently breastfeeding at the time of the survey. The most commonly reported galactagogues included lactation cookies (47%), brewer’s yeast (32%), fenugreek (22%) and domperidone (19%). The mean duration of use for each galactagogue ranged from 2 to 20 weeks. Approximately 1 in 6 women reported commencing galactagogues within the first week postpartum. Most women reported receiving recommendations to use herbal/dietary galactagogues from the internet (38%) or friends (25%), whereas pharmaceutical galactagogues were most commonly prescribed by General Practitioners (72%). The perceived effectiveness varied greatly across galactagogues. Perceived effectiveness was highest for domperidone (mean rating of 3.3 compared with 2.0 to 3.0 among other galactagogues). Over 23% of domperidone users reported experiencing multiple side effects, compared to an average of 3% of women taking herbal galactagogues.

Conclusions

This survey demonstrates that galactagogues use is common in Australia. Further research is needed to generate robust evidence about galactagogues’ efficacy and safety to support evidence-based strategies and improve breastfeeding outcomes.

Introduction

Breastfeeding is widely recognised to promote lifelong health for both the mother and infant [1]. International recommendations are exclusive breastfeeding until six months of age, with ongoing breastfeeding for two years or longer [2, 3]. In Australia, evidence indicates that the majority of women initiate breastfeeding at birth; however, by six months of age, only 60% are providing any breast milk, and 16% are exclusively breastfeeding [4]. This marked drop in exclusive breastfeeding has been observed in many other high-income countries [5]. Previous research shows that lactation insufficiency (also referred to as low breast milk supply), whether real or perceived, is one of the most common reasons women discontinue breastfeeding [6, 7]. Lactation insufficiency can be caused by several factors, including insufficient mammary tissue, irregular hormone levels, and ineffective milk removal from the breast [8].

The first-line management of lactation insufficiency involves non-pharmacological interventions, such as ensuring correct infant positioning and attachment [8, 9]. Where lactation insufficiency persists, galactagogues—the term used to describe substances thought to promote or increase breast milk production—may be used. Commonly reported galactagogues include dietary or herbal supplements, for example, oats or fenugreek, and pharmaceutical treatments such as domperidone [10]. Anecdotally, recent studies demonstrate widespread awareness and use of there is increased promotion of dietary galactagogues such as lactation cookies [11, 12]. An examination of widely promoted recipes and commercially available products indicates that lactation cookies contain highly variable combinations and quantities Internet searches outline a variety of ingredients, including oats, brewer’s yeast and flaxseed.

A recent Cochrane review on the use of oral galactagogues for increasing breast milk production in mothers of non-hospitalised term infants identified forty-one randomised clinical trials [10]. The review found uncertain evidence that galactagogues improve breast milk volume or longer-term breastfeeding outcomes [10]. In contrast, several high-quality studies have found domperidone effective in increasing breast milk production, specifically among mothers of preterm infants [13, 14]. However, the use of domperidone remains controversial. Domperidone use at doses above 30 mg daily may present a risk of serious cardiac side effects [15]. However the relevance to breastfeeding women has been questioned as previous data on increased cardiac risks mainly involved males and those aged over 60 years [16].

The considerable variation across studies concerning study population, intervention type, and outcome evaluation has led to ongoing treatment uncertainties. This is reflected in the recent guidelines issued by the Academy of Breastfeeding Medicine, which state that there is insufficient evidence to recommend one galactagogue over another [17].

Despite conflicting evidence regarding the benefits of galactagogues in clinical practice, there is evidence that breastfeeding women commonly use galactagogues, and use may be increasing. For example, a 2012 Australian survey of 304 breastfeeding women observed that 24% of respondents reported using a herbal galactagogue [18]. Estimates of uptake of the pharmaceutical galactagogue domperidone appear more variable. Studies based on prescribing/dispensing records from Australia, Canada and the UK show increasing trends in use, with varying overall prevalence of use ranging from 2.7% to 20% [1922]. In specific populations such as following preterm birth, prevalence appears even higher, up to 30% [19, 21]. Further, Grzeskowiak et al. examined queries relating to galactagogues at an Australian medicines information centre from 2001 to 2014 that demonstrated a significant trend towards increased phone calls regarding herbal galactagogues (0% to 23% of calls regarding galactagogues from 2001 to 2014) compared with a consistent interest in pharmaceutical galactagogues [23]. Unfortunately, the most recent studies evaluating galactagogue use only include data until 2015 and did not collect data on all types of galactagogues [12, 1820]. Therefore, we sought to undertake a survey to examine patterns of use of galactagogues, women’s experiences relating to use, as well as their perceptions regarding effectiveness.

Methods

Ethics

This study was approved by the Human Research Ethics Committee at the University of Adelaide (approval number H-2019033934).

Survey administration

Women currently living in Australia and either currently breastfeeding or who had previously breastfed were eligible to complete the survey. The survey was available online between 27 September 2019 and 12 December 2019. The survey consisted of part A, perceived safety and knowledge of galactagogues, and part B, personal experiences and use of galactagogues, including the self-perceived effectiveness, side effects and duration of use. If women had not taken any galactagogues, they did not complete part B of the survey. This paper will focus predominantly on part B of the survey. Questions included in the survey covered the timing and duration of use of substances, sources of recommendation, side effects experienced and perceived effectiveness. The perceived effectiveness of galactagogues was assessed using a 5-point Likert scale from 1 (Not at all effective) to 5 (Extremely effective). The survey was tested for face validity with two consumers and an academic breastfeeding expert. Only minor changes were made to the survey before formal distribution through social networks (i.e. Facebook, Twitter, email) of the Australian Breastfeeding Association [24, 25] (Australia’s national breastfeeding support service, assisting more than 80,000 women each year, with over 1100 breastfeeding counsellors available), Miracle Babies [26] (Australia’s leading organisation supporting premature and sick newborns, present in 143 Neonatal Intensive Care Units or Special Care Nurseries in Australia), as well as research networks of the author’s respective institutions (e.g. The Robinson Research Institute, and The University of Adelaide). Participants were encouraged to share the survey and post links to the survey through their own social networks. The survey was piloted with a small group of consumers (reviewed by representatives from the Australian Breastfeeding Association and Miracle Babies) and academic experts in survey design, resulting in minor modifications before the final survey was launched. The complete survey is available as S1 File.

Study data were collected and managed using Research Electronic Data Capture (REDCap) hosted at The University of Adelaide [27, 28]. REDCap is a secure, web-based software platform designed to support data capture for research studies, providing 1) an intuitive interface for validated data capture; 2) audit trails for tracking data manipulation and export procedures; 3) automated export procedures for seamless data downloads to standard statistical packages, and 4) procedures for data integration and interoperability with external sources. Only study investigators involved in the study had access to the data.

Completing the survey was voluntary, and no incentives were offered to participants. Respondents had the opportunity to submit their responses anonymously or could choose to include their contact details. When contact details were provided, respondents were approached to participate in a separate qualitative study investigating women’s experiences of using galactagogues. Only those who provided their contact details were able to withdraw their responses, however none elected to withdraw their responses. A total of 2152 responses were received, 7 responses were removed due to suspected duplicate entries based on identical maternal characteristics provided in the entry section, and a further 90 were removed due to births occurring outside of Australia.

Data analysis

Data were cleaned and analysed using STATA 14 (StataCorp LP, College Station, TX). Graphical images were produced using GraphPad Prism version 9 (GraphPad Software, La Jolla California USA) and R Upset Package [29]. Maternal demographic characteristics and data on use and experiences of galactagogues were described using descriptive statistics. The most common combinations of galactagogues used were graphed using an UpSet plot. Differences in maternal characteristics according to any galactagogue use were compared using Student’s T-test for means and Pearson’s Chi2 test for categorical variables. Duration of use was reported separately for each galactagogue according to those that were continuing use at the time of the survey and those that had stopped using it prior to completing the survey. Descriptive statistics were used to report the means and standard deviations. Where data were non-normally distributed, the median and inter-quartile ranges were used. Statistical significance was defined as a P < 0.05.

Results

A total of 1876 women responded to the survey. Maternal demographic characteristics of survey respondents are presented in Table 1. Briefly, the average age of women who responded was 31.5 years old, while most had completed secondary schooling or higher (92%) and almost half were primiparous (47%). At the time of the survey, 1217 (65%) of women reported they were currently breastfeeding their infant. For women who reported currently breastfeeding, the average infant age at the time of survey response was 10.7 months (mean ± 10 months standard deviation). Women who reported having ceased breastfeeding before completing the survey discontinued at an average of 21 months (mean ± 11 months standard deviation). Almost half of all respondents (49%) felt they could not produce enough breast milk for their child, and 63% sought help from a lactation consultant or breastfeeding expert. Of women who had stopped breastfeeding prior to completing the survey (35%), 19% reported stopping due to low milk supply.

Table 1. Maternal characteristics according to any reported use of a galactagogue during breastfeeding.

Total survey population Did not use galactagogue Used a galactagogue P-value*
n (%) n (%) n (%)
N (Total = 1876) 2055 756 1120
Mothers age at delivery (years; mean ± SD) 31.5 ± 4.8 32 ± 5.2 31.2 ± 4.5 <0.001
Youngest child’s age at survey 0.005
0–< 6 months 560 (30) 223 (30) 335 (30)
≥ 6–< 12 months 370 (20) 124 (17) 246 (22)
≥ 12 months 936 (50) 405 (54) 527 (48)
State/Territory of youngest child’s birth 0.291
Australian Capital Territory 88 (5) 40 (5) 48 (4)
New South Wales 453 (24) 192 (26) 259 (23)
Northern Territory 23 (1) 9 (1) 14 (1)
Queensland 322 (17) 111 (15) 210 (19)
South Australia 378 (20) 150 (20) 225 (20)
Tasmania 43 (2) 17 (2) 25 (2)
Victoria 407 (22) 176 (24) 231 (21)
Western Australia 150 (8) 55 (7) 94 (9)
Completed secondary school 1887 (92) 698 (93) 1027 (92) 0.834
Primiparous 882 (47) 255 (34) 625 (56) < 0.001
Multiple birth 39 (2) 14 (2) 25 (2) 0.578
Preterm birth 218 (12) 66 (9) 150 (14) 0.002
Caesarean-section 621 (33) 192 (26) 426 (38) <0.001
Perceived low milk supply 928 (49) 162 (22) 761 (68) <0.001
Saw a lactation consultant 1184 (63) 381 (51) 798 (71) <0.001
Supplemented with infant formula 561 (30) 111 (15) 446 (40) <0.001
Any smoking during breastfeeding 66 (4) 23 (3) 43 (4) 0.358

* Chi2 test between those that used and did not use a galactagogue.

Galactagogue use

Overall, 60% of women (n = 1120) reported taking one or more galactagogues during breastfeeding. Women who had preterm births, saw a lactation consultant, were primiparous, had perceived low milk supply, had a Caesarean section, or required supplemental feeding with infant formula were more likely to use galactagogues (Table 1).

Information on individual galactagogue use is presented in Table 2. The most commonly used galactagogue included lactation cookies (47%), brewer’s yeast (32%) and fenugreek (22%). The use of ‘Other’ galactagogues were reported by 7.3% (n = 137) of women, which included oats (n = 87; 4.7%), malt products (n = 42; 2.2%), and flaxseed or linseed (n = 13; 0.7%).

Table 2. Reported use of galactagogues and information sources from breastfeeding women (n = 1876).

Domperidone Metoclopramide Fenugreek Blessed Thistle Fennel Milk Thistle Ginger Brewer’s yeast Lactation cookies Combination of herbs
Took substance (n (%)) 355 (19) 21 (1) 421 (22) 98 (5) 157 (8) 40 (2) 52 (3) 592 (32) 884 (47) 109 (6)
Mothers age at birth (years; mean ± SD) 31.8 ± 4.6 34.1 ± 4.2 31.7 ± 4.4 31.7 ± 4.3 31.5 ± 4.5 31.5 ± 4.5 31.2 ± 4.9 30.9 ±4.4 31 ± 4.4 32.1 ± 4.4
Child’s age at survey*
0–6 months 110 (31) 2 (10) 105 (25) 29 (30) 44 (28) 13 (33) 19 (37) 158 (27) 264 (30) 42 (39)
6–12 months 79 (22) 4 (19) 86 (21) 18 (18) 43 (28) 8 (20) 16 (31) 135 (23) 210 (24) 23 (21)
12+ months 163 (46) 15 (71) 227 (54) 51 (52) 68 (44) 19 (48) 16 (31) 292 (50) 401 (46) 43 (40)
Maternal characteristics *
Primiparous 208 (59) 7 (33) 238 (57) 49 (50) 91 (58) 19 (48) 28 (54) 332 (56) 528 (60) 60 (55)
Preterm birth 74 (21) 7 (33) 70 (17) 17 (17) 22 (14) 9 (23) 7 (13) 85 (14) 125 (14) 14 (13)
Caesarean section 162 (46) 14 (67) 157 (37) 33 (34) 61 (39) 18 (45) 25 (48) 207 (35) 328 (37) 46 (42)
Perceived low milk supply 327 (92) 19 (90) 331 (79) 88 (90) 114 (73) 34 (85) 40 (77) 423 (71) 619 (70) 72 (66)
Took only this substance * 41 (12) 0 32 (8) 0 6 (4) 0 3 (6) 23 (4) 177 (20) 11 (10)
Two or more recommendation sources * 57 (16) 1 (5) 168 (40) 34 (35) 43 (27) 15 (38) 14 (27) 272 (46) 421 (48) 27 (25)
Who prescribed/recommended *
General Practitioner 271 (76) 14 (67) 30 (7) 5 (5) 3 (2) 1 (3) 3 (6) 22 (4) 21 (2) 2 (2)
Obstetrician/Gynaecologist 72 (20) 2 (10) 7 (2) 1 (1) 1 (1) 1 (2) 4 (1) 8 (1)
Midwife 41 (12) 2 (10) 67 (16) 14 (14) 8 (5) 3 (8) 3 (6) 65 (11) 87 (10) 6 (6)
Neonatologist/paediatrician 19 (5) 2 (10) 9 (2) 2 (2) 1 (0) 4 (0) 1 (1)
Internet search 119 (28) 30 (31) 54 (34) 20 (50) 17 (33) 278 (47) 356 (40) 34 (31)
Lactation consultant 90 (21) 26 (27) 18 (11) 6 (15) 3 (6) 76 (13) 117 (13) 9 (8)
Friends 87 (21) 15 (15) 28 (18) 11 (28) 12 (23) 211 (36) 395 (45) 26 (24)
Family 58 (14) 9 (9) 25 (16) 5 (13) 16 (31) 98 (17) 174 (20) 14 (13)
Child & family health nurse 45 (11) 8 (8) 5 (3) 2 (5) 1 (2) 35 (6) 60 (7)
Naturopath 40 (10) 14 (14) 29 (18) 8 (20) 7 (13) 23 (4) 17 (2) 16 (15)
Neonatal nurse 36 (9) 5 (5) 7 (4) 4 (10) 3 (6) 30 (5) 54 (6) 1 (1)
Mother’s group 33 (8) 4 (4) 11 (7) 2 (5) 4 (8) 56 (9) 112 (13) 4 (4)
Social media 34 (8) 5 (5) 11 (7) 3 (8) 5 (10) 91 (15) 160 (18) 11 (10)
Blogs or online discussion forums 24 (6) 4 (4) 6 (4) 1 (3) 5 (10) 56 (9) 77 (9) 4 (4)
Community pharmacist 24 (6) 4 (4) 4 (3) 18 (3) 15 (2) 5 (5)
Breastfeeding helpline 10 (2) 2 (1) 1 (2) 12 (2) 20 (2) 2 (2)
Books 6 (1) 1 (1) 3 (2) 8 (1) 7 (1) 2 (2)
Podcasts 1 (0) 1 (2) 1 (0) 3 (0) 1 (1)
Other 15 (4) 2 (10) 18 (4) 7 (7) 14 (9) 3 (8) 1 (2) 21 (4) 44 (5) 14 (13)

* (n (% of those who took each galactagogue)).

With respect to domperidone and metoclopramide, which are only available by prescription, these were most commonly prescribed by general practitioners (76% and 67% respectively), followed by obstetricians/gynaecologists (20% and 10% respectively). For the remaining galactagogues, the most common recommendation source was the internet (ranging from 28–50%) and friends (ranging from 15–45%). Healthcare professionals such as community pharmacists (2–6%), general practitioners (2–7%), and obstetricians/gynaecologists (1–2%) were uncommon sources of recommendation. One in three women taking herbal or dietary galactagogues reported using two or more recommendation sources.

Among those reporting galactagogue use, 27% took only one substance, while 46% used three or more galactagogues. The maximum number of galactagogues used was 10. The most common patterns of galactagogue use are represented in Fig 1. Lactation cookies featured in the top five different combinations of galactagogues used, and were the most used sole galactagogue.

Fig 1. UpSet plot showing the use of different galactagogues and combinations thereof in breastfeeding women (n = 1120).

Fig 1

Timing of commencement of galactagogues

Reported timing of commencement of galactagogue use is presented in Fig 2. Approximately 50% of galactagogues were commenced within the first four weeks postpartum, with 18.5% commenced within the first seven days. Timing of commencement varied considerably according to the individual type of galactagogue used. The proportion of women reporting commencing individual galactagogues within the first seven days postpartum, ranged from 4 to 67%.

Fig 2. Timing of commencement postpartum of galactagogues during breastfeeding.

Fig 2

Effectiveness

The perceived effectiveness of galactagogues is reported in Fig 3. The mean perceived effectiveness for eight of nine galactagogues was rated as being between ’slightly’ (2) and ’moderately’ (3) effective (Fig 3), except for domperidone which users reported as having the highest perceived effectiveness (3.3 ± 1.2; mean ± standard deviation).

Fig 3. Perceived effectiveness of galactagogues used by women who were breastfeeding (n = 1120).

Fig 3

Side effects

Side effects women experienced according to galactagogue use are presented in Table 3. Domperidone had the highest proportion of women reporting one or more side effects (45%), compared to less than 20% of women using herbal galactagogues. For domperidone and metoclopramide, 9% and 19% of women respectively stopped taking the medication due to side effects. Greater than 20% of domperidone users experienced two or more side effects.

Table 3. Self-reported side effects for galactagogues used by breastfeeding women (n = 1120).

Domperidone Metoclopramide Fenugreek Blessed thistle Fennel Milk thistle Ginger Brewer’s yeast Lactation cookies Combination of herbs
Took substance (N) 355 21 421 98 157 40 52 592 884 109
Any side effects * 159 (45) 6 (29) 72 (17) 8 (8) 7 (4) 4 (10) 3 (6) 65 (11) 110 (12) 5 (5)
Two or more side effects* 80 (23) 5 (24) 22 (5) 4 (4) 3 (2) 3 (8) 1 (2) 12 (2) 15 (2) 0 (0)
Individual side effects*
 Weight gain 88 (25) 2 (10) 10 (2) 1 (1) 2 (5) 1 (2) 20 (3) 79 (9) 1 (1)
 Headache 59 (17) 3 (14) 9 (2) 1 (1) 1 (3) 1 (2) 4 (1) 4 (0) 1 (1)
 Dry mouth 47 (13) 3 (14) 11 (3) 2 (2) 1 (1) 2 (5) 1 (2) 9 (2) 11 (1) 1 (1)
 Fatigue 31 (9) 3 (14) 4 (1) 2 (2) 6 (1)
 Irritability 22 (6) 3 (14) 2 (0) 1 (3) 3 (1) 4 (0) 1 (1)
 Depression 20 (6) 2 (10) 3 (1) 3 (1) 3 (0)
 Stomach cramps 14 (4) 17 (4) 3 (3) 3 (2) 16 (3) 13 (1)
 Nausea 13 (4) 3 (14) 11 (3) 3 (3) 4 (3) 1 (3) 1 (2) 11 (2) 4 (0)
 Heart palpitations /racing heart 13 (4) 3 (14) 3 (1) 2 (0) 2 (0)
 Dizziness /fainting 12 (3) 5 (1) 1 (1) 1 (3) 4 (1) 5 (1)
 Involuntary movements /jerking 4 (1) 2 (10)
 Skin rash 2 (1) 2 (0) 1 (0) 1 (0)
 Other 12 (3) 14 (3) 1 (1) 2 (1) 7 (1) 12 (1) 1 (1)
  Body odour 11 (3)
  Decreased supply 6 (1)
  Gas/bloating 8 (1)

* n (% of those who took each galactagogue).

Duration of use

The median reported duration of use for each galactagogue is presented in Fig 4. Overall, the median reported duration of use was longer in women who were currently taking a galactagogue at the time of the survey completion. Median durations of use varied from 2 (ginger) to 7 (combination of herbs) weeks for those who had stopped using a substance, and 6 (milk thistle) to 19 weeks (ginger) for those who were continuing use at the time of the survey.

Fig 4. Duration of galactagogue use by women who had (a) stopped use and those who are (b) continuing use at the time of survey completion (median, inter-quartile range, and 5th to 95th percentile whiskers).

Fig 4

Recommendations

The percentages of women who would recommend a particular galactagogue to a friend is presented in Fig 5. Overall, 75% would recommend a galactagogue to a friend. There appeared to be a strong correlation between the perceived effectiveness of a galactagogue and whether or not women would recommend it to a friend. Of the 25% of women who would not recommend to a friend, 71% indicated a perceived lack of effectiveness as a reason.

Fig 5. Women’s recommendations of galactagogues to a friend and their reasons for not recommending.

Fig 5

Discussion

In this large contemporary survey of Australian women, galactagogue use was reported by 60% of women at some stage during their lactation. Women commonly reported using multiple galactagogues, with median durations of use from 2–19 weeks or more and 50% of galactagogues being commenced within the first four weeks postpartum. Galactagogues appeared to be well tolerated, except for pharmaceutical galactagogues, where side effects were reported by approximately 50% of women. The widespread utilisation and experiences of galactagogues in postpartum women highlights the importance of future research aimed at (a) understanding why women are using them in the face of limited evidence and guidance about their use, and (b) improving evidence regarding the efficacy and safety of individual galactagogues to support informed decision making.

The need to develop additional strategies to support breastfeeding mothers is reflected in nearly half of our sample reporting that they felt they could not produce enough milk for their child at some stage, with almost 1 in 5 women discontinuing breastfeeding due to concerns about their milk supply. It is uncertain whether concerns related to breast milk supply were real or perceived, determining which has been often recognised as a common challenge within clinical practice settings [6]. The high proportion of women reporting concerns about their breast milk production in our study (approximately 50%) is consistent with previous studies from Australia (45%) and the United States (76%) [12, 30].

Our data showed that women were more likely to take a galactagogue based on several pregnancy/birth characteristics such as primiparity, preterm birth or caesarean delivery, as well as perceived low breast milk supply. These risk factors are consistent with those previously reported in the literature, and commonly associated with breastfeeding difficulties [8, 22, 31].

A previous 2012 survey of women in Western Australia found that 24% of 304 respondents reported using a herbal galactagogue during breastfeeding [18]. The most common galactagogues included fenugreek (18%), blessed thistle (6%) and fennel (5%) [18]. In comparison, a 2015 US survey of 188 women reported herbal galactagogue use in 46% of respondents [12]. The most common galactagogues were fenugreek (46%), fennel (16%) and milk thistle (13%) [12]. However, the survey was restricted to women who reported using or intending to use galactagogues. Notably, neither of these studies collected data regarding the use of the dietary galactagogues lactation cookies or brewer’s yeast which were the most commonly reported galactagogues in our survey. Regarding the use of herbal galactagogues, we observed similar high usage of fenugreek, and lower but notable use of fennel [12]. The number of women reporting using domperidone in our survey (1 in 5 respondents) was higher than initially anticipated. A previous Australian audit of domperidone use in the postpartum period at a single tertiary maternity teaching hospital from 2000 to 2010 reported a prevalence of 5% [19]. However, as the audit was restricted to domperidone supplied from the hospital pharmacy department, it likely represents an underestimation of total use [19]. By comparison, international studies evaluating domperidone use from 2011 to 2015 have produced widely varying prevalence ranging from 2% in the UK [20] 2.7% in the US [12], and 20% in Canada [21]. Among high-risk subgroups, such as women with preterm birth, the prevalence of domperidone use increased to 30% [19, 21]. Such differences may reflect differences in inter-country domperidone availability, clinical practice guidelines and prescriber/consumer awareness.

Domperidone had the highest perceived effectiveness rating but also had the highest proportion of women reporting side effects. While previous meta-analyses provide moderate-quality evidence to support the use of domperidone in managing lactation insufficiency following preterm birth [13], there is no such equivalent evidence that it is effective in mothers of otherwise healthy term infants [10]. This represents a significant evidence-gap given widespread uptake of domperidone use following term birth.

While fenugreek was the most commonly used herbal galactagogue and appeared to be well-tolerated, a recent meta-analysis demonstrated that it seems to be no more effective than a placebo in treating lactation insufficiency [10, 32].

The observation that a high proportion of women are taking galactagogues based on recommendations from the internet is consistent with a 2015 survey conducted in the United States demonstrated that 48% of women taking fenugreek sourced their information online. The same study also found that up to 85% of women sought information from sources other than their primary care provider or lactation consultants [12]. Frequent use of information sources other than healthcare professionals raises concerns regarding whether or not women are being provided with evidence-based information regarding the use of galactagogues to support informed decision making. This is backed up by findings from an Australian survey of women’s attitudes to herbal medicine during lactation that found that while the internet was again a common source of information, women often doubted the reliability of information from the internet and cited the need for information and resources endorsed by reputable breastfeeding organisations and healthcare professionals [30, 33]. The second highest source of information was women’s friends, which may suggest that women prioritise others’ anecdotal experiences over that of evidence-based resources or trained health care professionals.

The fact that 1 in 6 respondents started using various galactagogues within the first seven days postpartum raises potential concerns, particularly given the challenge of assessing the adequacy of breast milk production in the early postpartum period [34, 35]. These findings may indicate that women may be turning to galactagogues prophylactically (without actually having low breast milk supply) or using them as early treatments before trying non-pharmacological strategies. While 71% of women reported seeing a lactation consultant, we do not know when this occurred relative to the commencement of galactagogues. The observation that 20% of galactagogue use occurred after three months postpartum highlights the importance of continued breastfeeding support beyond the immediate postpartum period.

Strengths and limitations

This survey is the first to examine galactagogue use, the timing and duration of use, as well as perceived effectiveness and side effects of common galactagogues in the community. This study has several limitations. Our survey used non-probabilistic sampling and snowballing sampling techniques, making it difficult to extrapolate findings to the broader Australian population of breastfeeding women. Based on national Australian perinatal statistics, while our survey included a higher proportion of women born in Australia (86% vs 65%), the distribution of other key demographic and birth characteristics known to influence breastfeeding outcomes such as maternal age at delivery (31.5 years vs. 30.4 years), delivery by caesarean section (33% vs. 35%), preterm birth (12% vs. 9%), and prevalence of overweight/obese (49% vs 45%), were similar [36].

The survey measured women’s perceived effectiveness and did not utilise objective measures of changes in breast milk supply. The support and clinical care women received during breastfeeding were also not reported, meaning some women’s perceived increase in supply may have been unrelated to galactagogue use.

Lactation cookies were provided as one of ten listed galactagogues that women could choose from. However participants were not provided with a definition of lactation cookies nor a pre-defined list of ingredients. As such, our survey did not account for possible variations in ingredients between different lactation cookies, and there is likely to be some crossover with other galactagogues listed in the survey, particularly brewer’s yeast which is one of the most common ingredients in lactation cookies. While 1217 women were breastfeeding at the time of the survey, responses were obtained from 657 women who had completed breastfeeding up to an average of 3.9 years before completing the survey. This raises the possibility of errors related to women’s ability to recall exact timings and durations of use correctly. However, previous studies suggest the degree of error is likely to be small, with a 1-month error in reporting among women recalling information from 1 to 3.5 years prior [37]. Furthermore, for women continuing to breastfeed and taking a galactagogue at the time of completing the survey, it is not possible to correctly define the total duration of use or their complete set of experiences. Lastly, we did not ask about galactagogue use before birth. Some women use herbal galactagogues before birth to stimulate lactation initiation, which is of concern as some popular herbal galactagogues such as fenugreek and milk thistle may cause uterine contractions [38].

Concluding remarks

This large online survey demonstrates that the use of galactagogues appears to be very common in Australia. Women seem to be using multiple galactagogues during breastfeeding, with evidence of frequent initiation in the first week postpartum and long durations of use. The incidence of side effects appeared higher for women taking pharmaceutical agents compared to herbal galactagogues. However, a number of side effects were still reported by women using herbal or food-based galactagogues, suggesting they are not completely benign. The high prevalence of women taking galactagogues based on recommendations obtained through the internet or friends, rather than healthcare providers, raises concerns surrounding the potential quality of the information they receive, particularly in light of the lack of evidence surrounding the effectiveness and safety of most galactagogues. Overall, our findings highlight the need for further high-quality research, particularly appropriately powered randomized controlled trials, to generate robust evidence about the efficacy and safety of galactagogues to support evidence-based strategies to improve breastfeeding outcomes.

Supporting information

S1 File. Boosting breast milk supply survey.

All survey questions asked regarding women’s use and experiences with substances to boost breast milk supply.

(PDF)

Data Availability

Data cannot be shared publicly because the ethics committee restricts secondary use of the data currently. Data are available from The University of Adelaide Human Research Ethics Committee (contact T: +61 8 8313 5137 | F: +61 8 8313 3700 | research.services@adelaide.edu.au) for researchers who meet the criteria for access to confidential data.

Funding Statement

GM was supported by an Australian Government Research Training Program Scholarship. AK was supported by a National Health and Medical Research Council Early Career Fellowship (GNT1161379). LG receives salary support through a Mid-Career Research Fellowship provided by The Hospital Research Foundation (C-MCF-10-2019). LA, AR, GZ and LG were awarded a Robinson Research Institute Engaging Opportunities Grant 2019. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

  • 1.Victora CG, Bahl R, Barros AJ, Franca GV, Horton S, Krasevec J, et al. Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. Lancet. 2016;387(10017):475–90. doi: 10.1016/S0140-6736(15)01024-7 [DOI] [PubMed] [Google Scholar]
  • 2.Kramer MS, Kakuma R. Optimal duration of exclusive breastfeeding. Cochrane Database Syst Rev. 2012(8):CD003517. doi: 10.1002/14651858.CD003517.pub2 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.COAG Health Council. Australian National Breastfeeding Strategy: 2019 and beyond. Canberra, Department of Health; 2019. [Google Scholar]
  • 4.Australian Institute of Health and Welfare. 2010 Australian National Infant Feeding Survey: Indicator Results. 2011. [Google Scholar]
  • 5.World Health Organization. Infant and young child feeding: World Health Organization; 2020. [updated 1 April 2020. https://www.who.int/news-room/fact-sheets/detail/infant-and-young-child-feeding. [Google Scholar]
  • 6.Amir LH. Breastfeeding: managing ’supply’ difficulties. Aust Fam Physician. 2006;35(9):686–9. [PubMed] [Google Scholar]
  • 7.Australian Health Ministers’ Conference. The Australian National Breastfeeding Strategy 2010–2015. Canberra; 2009.
  • 8.Amir LH. Managing common breastfeeding problems in the community. BMJ. 2014;348:g2954. doi: 10.1136/bmj.g2954 [DOI] [PubMed] [Google Scholar]
  • 9.Morton J, Hall JY, Wong RJ, Thairu L, Benitz WE, Rhine WD. Combining hand techniques with electric pumping increases milk production in mothers of preterm infants. J Perinatol. 2009;29(11):757–64. doi: 10.1038/jp.2009.87 [DOI] [PubMed] [Google Scholar]
  • 10.Foong SC, Tan ML, Foong WC, Marasco LA, Ho JJ, Ong JH. Oral galactagogues (natural therapies or drugs) for increasing breast milk production in mothers of non-hospitalised term infants. Cochrane Database Syst Rev. 2020;5:CD011505. doi: 10.1002/14651858.CD011505.pub2 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Zizzo G, Amir LH, Moore V, Grzeskowiak LE, Rumbold AR. The risk-risk trade-offs: Understanding factors that influence women’s decision to use substances to boost breast milk supply. PLoS One. 2021;16(5):e0249599. doi: 10.1371/journal.pone.0249599 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Bazzano AN, Cenac L, Brandt AJ, Barnett J, Thibeau S, Theall KP. Maternal experiences with and sources of information on galactagogues to support lactation: a cross-sectional study. Int J Womens Health. 2017;9:105–13. doi: 10.2147/IJWH.S128517 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Grzeskowiak LE, Smithers LG, Amir LH, Grivell RM. Domperidone for increasing breast milk volume in mothers expressing breast milk for their preterm infants: a systematic review and meta-analysis. BJOG. 2018;125(11):1371–8. doi: 10.1111/1471-0528.15177 [DOI] [PubMed] [Google Scholar]
  • 14.Grzeskowiak LE, Wlodek ME, Geddes DT. What evidence do we have for pharmaceutical galactagogues in the treatment of lactation insufficiency?-A narrative review. Nutrients. 2019;11(5). doi: 10.3390/nu11050974 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Sewell CA, Chang CY, Chehab MM, Nguyen CP. Domperidone for lactation: what health care providers need to know. Obstet Gynecol. 2017;129(6):1054–8. doi: 10.1097/AOG.0000000000002033 [DOI] [PubMed] [Google Scholar]
  • 16.Grzeskowiak LE. Domperidone for lactation: what health care providers really should know. Obstet Gynecol. 2017;130(4):913-. doi: 10.1097/AOG.0000000000002286 [DOI] [PubMed] [Google Scholar]
  • 17.Brodribb W. ABM Clinical Protocol #9: Use of galactogogues in initiating or augmenting maternal milk production, second revision 2018. Breastfeed Med. 2018;13(5):307–14. doi: 10.1089/bfm.2018.29092.wjb [DOI] [PubMed] [Google Scholar]
  • 18.Sim TF, Sherriff J, Hattingh HL, Parsons R, Tee LB. The use of herbal medicines during breastfeeding: a population-based survey in Western Australia. BMC Complement Altern Med. 2013;13. doi: 10.1186/1472-6882-13-317 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Grzeskowiak LE, Lim SW, Thomas AE, Ritchie U, Gordon AL. Audit of domperidone use as a galactogogue at an Australian tertiary teaching hospital. J Hum Lact. 2013;29(1):32–7. doi: 10.1177/0890334412459804 [DOI] [PubMed] [Google Scholar]
  • 20.Mehrabadi A, Reynier P, Platt RW, Filion KB. Domperidone for insufficient lactation in England 2002–2015: A drug utilization study with interrupted time series analysis. Pharmacoepidemiol Drug Saf. 2018;27(12):1316–24. doi: 10.1002/pds.4621 [DOI] [PubMed] [Google Scholar]
  • 21.Smolina K, Morgan SG, Hanley GE, Oberlander TF, Mintzes B. Postpartum domperidone use in British Columbia: a retrospective cohort study. CMAJ Open. 2016;4(1):E13–9. doi: 10.9778/cmajo.20150067 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Grzeskowiak LE, Dalton JA, Fielder AL. Factors associated with domperidone use as a galactogogue at an Australian tertiary teaching hospital. J Hum Lact. 2015;31(2):249–53. doi: 10.1177/0890334414557175 [DOI] [PubMed] [Google Scholar]
  • 23.Grzeskowiak LE, Hill M, Kennedy DS. Phone calls to an Australian pregnancy and lactation counselling service regarding use of galactagogues during lactation—the MotherSafe experience. Aust N Z J Obstet Gynaecol. 2018;58(2):251–4. doi: 10.1111/ajo.12731 [DOI] [PubMed] [Google Scholar]
  • 24.Australian Breastfeeding Association. About the Australian Breastfeeding Association (ABA): Australian Breastfeeding Academy; 2021. [https://www.breastfeeding.asn.au/aboutaba. [Google Scholar]
  • 25.Australian Breastfeeeding Association. Australian Breastfeeding Association for Health Professionals: Australian Breastfeeeding Association,; 2021. [https://abaprofessional.asn.au/about-us/. [Google Scholar]
  • 26.Miracle Babies Foundation. Miracle Babies Foundation: Find a Hospital: Miracle Babies Foundation,; 2021. [https://www.miraclebabies.org.au/event-search.php?linkid=1394. [Google Scholar]
  • 27.Harris PA, Taylor R, Minor BL, Elliott V, Fernandez M, O’Neal L, et al. The REDCap consortium: Building an international community of software platform partners. J Biomed Inform. 2019;95:103208. doi: 10.1016/j.jbi.2019.103208 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)—a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):377–81. doi: 10.1016/j.jbi.2008.08.010 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Conway JR, Lex A, Gehlenborg N. UpSetR: an R package for the visualization of intersecting sets and their properties. Bioinformatics. 2017;33(18):2938–40. doi: 10.1093/bioinformatics/btx364 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.Sim TF, Hattingh HL, Sherriff J, Tee LB. The use, perceived effectiveness and safety of herbal galactagogues during breastfeeding: A qualitative study. Int J Environ Res Public Health. 2015;12(9):11050–71. doi: 10.3390/ijerph120911050 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Brown CR, Dodds L, Legge A, Bryanton J, Semenic S. Factors influencing the reasons why mothers stop breastfeeding. Can J Public Health. 2014;105(3):e179–85. doi: 10.17269/cjph.105.4244 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.Grzeskowiak LE. No evidence that fenugreek is more effective than placebo as a galactagogue. Phytother Res. 2021;35(4):1686–7. doi: 10.1002/ptr.6914 [DOI] [PubMed] [Google Scholar]
  • 33.Sim TF, Hattingh HL, Sherriff J, Tee LB. Perspectives and attitudes of breastfeeding women using herbal galactagogues during breastfeeding: a qualitative study. BMC Complement Altern Med. 2014;14. doi: 10.1186/1472-6882-14-216 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Kent JC, Gardner H, Geddes DT. Breastmilk production in the first 4 weeks after birth of term infants. Nutrients. 2016;32(12):756. doi: 10.3390/nu8120756 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Neville MC, Keller R, Seacat J, Lutes V, Neifert M, Casey C, et al. Studies in human lactation: milk volumes in lactating women during the onset of lactation and full lactation. Am J Clin Nutr. 1988;48(6):1375–86. doi: 10.1093/ajcn/48.6.1375 [DOI] [PubMed] [Google Scholar]
  • 36.Australian Institute of Health and Welfare. Australia’s mothers and babies 2018: in brief. Canberra: AIHW; 2018. [Google Scholar]
  • 37.Gillespie B, d’Arcy H, Schwartz K, Bobo JK, Foxman B. Recall of age of weaning and other breastfeeding variables. Int Breastfeed J. 2006;1:4. doi: 10.1186/1746-4358-1-4 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 38.Zapantis A, Steinberg JG, Schilit L. Use of herbals as galactagogues. J Pharm Pract. 2012;25(2):222–31. doi: 10.1177/0897190011431636 [DOI] [PubMed] [Google Scholar]

Decision Letter 0

Jane Anne Scott

24 May 2021

PONE-D-21-14565

Use and experiences of galactagogues while breastfeeding among Australian women

PLOS ONE

Dear Dr. Grzeskowiak,

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.

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Jane Anne Scott, PhD, MPH Grad Dip Dietetics, BSc

Academic Editor

PLOS ONE

Additional Editor Comments:

  1. As requested by reviewer 1, please identify the relevant ingredients in ‘lactation cookies’.

  2. Please carefully edit the methods section to avoid unnecessary repetition. For instance, reference to the use of R Upset Package is made on line 135 and then again on line 138. Can these sentences be combined to avoid repetition? Similarly, the method for reporting perceived effectiveness of galactagogues is first described on lines 105-107 and then again on lines 140-141.

  3. Line 144 data is the plural of datum should read ‘data were’. Please check for any other instances.

  4. Table 1 p values of 0.000 should be reported as p<0.001

  5. The sentence started on line 198 is incomplete

  6. There is some ambiguity related to the statement made in line 251.

Where do you provide the evidence for the statement that 1 in 5 women discontinued breastfeeding before they desired? In lines 159-160 you report “Of women who had stopped breastfeeding prior to completing the survey (35%), 19% reported stopping due to low milk supply.” In which case the 35% of women who stopped prior to completing the survey may have stopped for this reason but not all may necessarily have stopped prior to when they wanted to.

Furthermore, the statement "with almost 1 in 5 women discontinuing breastfeeding earlier than  desired because of concerns about their milk supply” is ambiguous and implies that 1 in 5 of the study sample discontinued breastfeeding earlier than desired for this reason  rather than 1 in 5 women who discontinued breastfeeding earlier than desired gave this reason for stopping.  Is this statement based on the results reported on lines 159-160?

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.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

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

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Reviewer #1: Yes

Reviewer #2: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

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Reviewer #1: No

Reviewer #2: Yes

**********

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Reviewer #1: Yes

Reviewer #2: Yes

**********

5. 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: A well written paper with important information about the use of galactagogues.

Just a few points for consideration:

1. Probably typo errors in the sentences in Lines 137-138 “The most common combinations of galactagogue use were graphed using the ‘UpSetR’ package in R.” and Lines 198-199 “The proportion of women reporting commencing individual galactagogues within the first seven days postpartum, ranged from.”

2. Perhaps the authors could consider editing the sentence in Lines 71-73 to make it easier to understand? Also would the authors consider improving the way the two sentences in Lines 182-185 flowed?

3. With reference to Lines 130-132: Were there many participants who withdrew their responses when contacted during the separate qualitative study? Were there a lot of duplicate entries found during the search? A flow diagram capturing these details might be useful.

4. The data (percentages) in lines 211 to 215 is somewhat confusing to me. I could not tie this with the figures reported in Table 3.

5. What are lactation cookies made of? Perhaps some information about lactation cookies and the possible ingredients in the cookies that could have acted as a galactagogue could be mentioned in the background.

6. Lines 244 -248: Perhaps an emphasis on the need for properly conducted and properly described randomized controlled studies could be added after the call for future research? The main reason why there are extremely limited evidence on galactagogue efficacy is not because studies have not been done (there are over 100 studies as of year 2020), but there were problems with the research methods used (many were just observational studies) and the way the research was reported/described which prevented us from drawing firm findings. Another huge weakness of most studies is the lack of exploration of potential side effects, as well as long-term breastfeeding outcomes. (Lines 67-68 mentioned that “The review found uncertain evidence that galactagogues improve ……. longer-term breastfeeding outcomes” The lack of evidence here indeed was because there were no studies exploring this outcome.)

7. Lines 268-270: Would the authors have data on which ethnic group used which galactagogue? (eg was ginger more popular with the Chinese?) It would be interesting it this data was available.

Reviewer #2: Thank you for the opportunity to review this interesting and well-written manuscript. It reports important findings resulting from a technically sound piece of scientific research. I have provided some minor suggestions and comments for consideration.

Introduction

Line 48: Please consider minor revision of the important first sentence with respect to the word "benefit".

Language used to describe lactation can have unintended interpretations. As noted in the third sentence, lactation is a phase of the reproductive cycle that statistics show is not functioning to recommendations. The description of breastfeeding as conferring “benefits” is problematic because it can be interpreted to imply that lactation is a beneficial optional extra, rather than a phase of the reproductive cycle that is the biologic norm (for example, we don’t typically talk about the “benefits” of effective heart function). Health outcomes are poorer for both mother and infant if this biologic norm is not sustained to recommendations.

Line 49: For similar reasons, please also consider changing the word “promote” to “recommend”.

Line 60: The reference cited does not cite evidence for association of correct positioning and latch with improvement in milk synthesis. Suggest alternative of ensuring maximal breast drainage (such as via increased breastfeed frequency +/- hand expression and/or pumping) as an evidence-based example of a strategy that increases milk synthesis.

Dewey KG, Lönnerdal B. Infant self‐regulation of breast milk intake. Acta Paediatrica. 1986;75(6):893-8.

Daly SE, Hartmann PE. Infant demand and milk supply. Part 2: The short-term control of milk synthesis in lactating women. Journal of Human Lactation. 1995;11(1):27-37.

Morton J, Hall JY, Wong RJ, Thairu L, Benitz WE, Rhine WD. Combining hand techniques with electric pumping increases milk production in mothers of preterm infants. Journal of perinatology : official journal of the California Perinatal Association. 2009;29(11):757-64.

Line 62: Breast milk supply includes consideration of both maternal milk synthesis and transfer of milk to the infant via breastfeeding or breast milk feeding. Suggest replacement of “supply” with “synthesis” as galactogogues only have the possibility of affecting maternal synthesis.

Methods

Inclusion of the survey as an appendix or supplement would be very helpful.

Results

Table 2: One bracket missing (Fennel; child’s age at survey 12+months)

Line 199: Some text missing

Figures 2 & 5: For me, the inclusion of colour assists with interpretation of these figures, however, perhaps consider ensuring that colour selection is colourblind-friendly.

Discussion

Line 240: Objectively, this study is surveying the experience relating to galactogogue use during lactation function. Suggest deletion of “experience” descriptor for lactation.

General comments for consideration, but not essential for inclusion:

These findings suggest none of the galactogogues are being used in a way that meets minimum quality use of medicine principles for safety and efficacy.

First, there is the lack of appropriate diagnosis to determine whether maternal concerns regarding lactation insufficiency are actual or just perceived and, if actual, to investigate the cause.

If lactation insufficiency is actual, this can be caused by a number of factors, including infant factors resulting in ineffective milk removal that subsequently cause down-regulation of milk synthesis (as stated in the introduction). This is of course further complicated by the lack of objective tests to assess milk production available in routine clinical practice.

Second, there is generally poor or absent evidence for understanding of galactogogue mechanism of action. Even domperidone, where the mechanism is known, is presumably commenced without investigation to determine whether low plasma prolactin is the cause of lactation insufficiency. Further, interpretation of plasma prolactin measurement itself is complicated by the absence of reference ranges for plasma prolactin in lactating women.

How concerning that maternal galactogogue use is so prevalent given that the cause (if lactation insufficiency is actually present) may not even be due to any disruption of maternal physiology, thus rendering the galactogogue without rationale for use and giving greater weight to any incidence of adverse effects. Clearly, women are worried about the adequacy of their breastmilk production and better strategies need to be developed to deliver effective support.

Well done, a thought-provoking study.

**********

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Reviewer #1: Yes: Siew Cheng Foong

Reviewer #2: Yes: Melinda Boss

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PLoS One. 2021 Jul 1;16(7):e0254049. doi: 10.1371/journal.pone.0254049.r002

Author response to Decision Letter 0


7 Jun 2021

Dear Editor,

Thank you for the feedback and for the opportunity to revise the manuscript.

We value the opportunity to further improve this manuscript with the following changes outlined below. Line numbers correspond to line numbers in the tracked changes copy of the document.

Additional Editor Comments:

1. As requested by reviewer 1, please identify the relevant ingredients in ‘lactation cookies’.

Response 1: The following text has been added at line 68; ‘Anecdotally, recent studies demonstrate widespread awareness and use of galactagogues such as lactation cookies (Zizzo et al 2021). An examination of widely promoted recipes and commercially available products indicates that lactation cookies contain highly variable combinations and quantities of ingredients, including oats, brewer’s yeast and flaxseed.’, and line 359 regarding lactation cookies; ‘Lactation cookies were provided as one of ten listed galactagogues that women could choose from. However participants were not provided with a definition of lactation cookies nor a pre-defined list of ingredients. As such, our survey did not account for possible variations in ingredients between different lactation cookies, and there is likely to be some crossover with other galactagogues listed in the survey, particularly brewer’s yeast which is one of the most common ingredients in lactation cookies.’

2. Please carefully edit the methods section to avoid unnecessary repetition. For instance, reference to the use of R Upset Package is made on line 135 and then again on line 138. Can these sentences be combined to avoid repetition? Similarly, the method for reporting perceived effectiveness of galactagogues is first described on lines 105-107 and then again on lines 140-141.

Response 2: The repeating use of ‘R Upset package’ terms in line 157 has been amended to; ‘The most common combinations of galactagogues used were graphed using an UpSet plot.’

The repeating phrase on line 160-161 has been removed, and line 119-121 amended to; ‘ The perceived effectiveness of galactagogues was assessed using a 5-point Likert 5-point Likert scale from 1 (Not at all effective) to 5 (Extremely effective).’

3. Line 144 data is the plural of datum should read ‘data were’. Please check for any other instances.

Response 3: This error has been amended in text (line 164), and no other instances were found.

4. Table 1 p values of 0.000 should be reported as p<0.001

Response 4: This has been amended in the Table 1.

5. The sentence started on line 198 is incomplete

Response 5: The following amendment has been made to line 220, where the underlined text has been added; ‘The proportion of women reporting commencing individual galactagogues within the first seven days postpartum, ranged from 4 to 67%.’

6. There is some ambiguity related to the statement made in line 251.

Where do you provide the evidence for the statement that 1 in 5 women discontinued breastfeeding before they desired? In lines 159-160 you report “Of women who had stopped breastfeeding prior to completing the survey (35%), 19% reported stopping due to low milk supply.” In which case the 35% of women who stopped prior to completing the survey may have stopped for this reason but not all may necessarily have stopped prior to when they wanted to.

Furthermore, the statement "with almost 1 in 5 women discontinuing breastfeeding earlier than desired because of concerns about their milk supply” is ambiguous and implies that 1 in 5 of the study sample discontinued breastfeeding earlier than desired for this reason rather than 1 in 5 women who discontinued breastfeeding earlier than desired gave this reason for stopping. Is this statement based on the results reported on lines 159-160?

Response 6: This statement has now been removed. Unfortunately we did not ask about whether or not breastfeeding was discontinued earlier than desired and are therefore not in a position to clarify this ambiguity.

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.

When submitting your revision, we need you to address these additional requirements.

Two additional citations have been added during the revision process, the first is:

11. Zizzo G, Amir LH, Moore V, Grzeskowiak LE, Rumbold AR. The risk-risk trade-offs: Understanding factors that influence women's decision to use substances to boost breast milk supply. PLoS One. 2021;16(5):e0249599.

This is a recent publication since the original paper was submitted, which demonstrates women’s use of lactation cookies, to support response one to the editor. The next paper added was:

9. Morton J, Hall JY, Wong RJ, Thairu L, Benitz WE, Rhine WD. Combining hand techniques with electric pumping increases milk production in mothers of preterm infants. J Perinatol. 2009;29(11):757-64.

This reference was added to support response 2 to reviewer 2.

2. Please include additional information regarding the survey or questionnaire used in the study and ensure that you have provided sufficient details that others could replicate the analyses. For instance, if you developed a questionnaire as part of this study and it is not under a copyright more restrictive than CC-BY, please include a copy, in both the original language and English, as Supporting Information. If the original language is written in non-Latin characters, for example Amharic, Chinese, or Korean, please use a file format that ensures these characters are visible.

Response: The following has been added at line 134; ‘The complete survey is available as a supporting file (SI File 1).’ And a copy of the survey will be uploaded as a supporting file.

3. Please state whether you validated the questionnaire prior to testing on study participants. Please provide details regarding the validation group within the methods section.

Response: The following has been added at line 121-123; ‘The survey was tested for face validity with two consumers and an academic breastfeeding expert. Only minor changes were made to the survey before formal distribution…’

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.

a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially identifying or sensitive patient information) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent.

Data cannot be shared publicly because the ethics committee restricts secondary use of the data currently. Data are available from The University of Adelaide Human Research Ethics Committee (contact T: +61 8 8313 5137; F: +61 8 8313 3700; research.services@adelaide.edu.au) for researchers who meet the criteria for access to confidential data.

Reviewers' comments:

Reviewer #1: A well written paper with important information about the use of galactagogues.

Just a few points for consideration:

1. Probably typo errors in the sentences in Lines 137-138 “The most common combinations of galactagogue use were graphed using the ‘UpSetR’ package in R.” and Lines 198-199 “The proportion of women reporting commencing individual galactagogues within the first seven days postpartum, ranged from.”

Response 1: The following amendment has been made to line 157, ‘The most common combinations of galactagogues used were graphed using an UpSet plot.’

The following amendment has been made to line 218-220, where the underlined text has been added; ‘The proportion of women reporting commencing individual galactagogues within the first seven days postpartum, ranged from 4 to 67%.’

2. Perhaps the authors could consider editing the sentence in Lines 71-73 to make it easier to understand? Also would the authors consider improving the way the two sentences in Lines 182-185 flowed?

Response 2: The following change has been made to lines 80-84; ‘Domperidone use at doses above 30 mg daily may present a risk of serious cardiac side effects (12). However the relevance to breastfeeding women has been questioned as previous data on increased cardiac risks mainly involved males and those aged over 60 years (13).’

The following change has been made to lines 202-205; ‘The most common patterns of galactagogue use are represented in Figure 1. Lactation cookies featured in the top five different combinations of galactagogues used, and were the most used sole galactagogue.’

3. With reference to Lines 130-132: Were there many participants who withdrew their responses when contacted during the separate qualitative study? Were there a lot of duplicate entries found during the search? A flow diagram capturing these details might be useful.

Response 3: The following amendment to line 146-151 have been made; ‘Only those who provided their contact details were able to withdraw their responses, however none elected to withdraw their responses. A total of 2152 responses were received, 7 responses were removed due to suspected duplicate entries based on identical maternal characteristics provided in the entry section, and a further 90 were removed due to births occurring outside of Australia.’

4. The data (percentages) in lines 211 to 215 is somewhat confusing to me. I could not tie this with the figures reported in Table 3.

Response 4: The line in Table 3 has been changed to reflect ‘Any side effects’ rather than ‘No side effects’ and following has been changed in line 234-235; ‘Domperidone had the highest proportion of women reporting one or more side effects (45%),’

5. What are lactation cookies made of? Perhaps some information about lactation cookies and the possible ingredients in the cookies that could have acted as a galactagogue could be mentioned in the background.

Response 5: As above in response 1:

The following text has been added at line 68; ‘Anecdotally, recent studies demonstrate widespread awareness and use of galactagogues such as lactation cookies (Zizzo et al 2021). An examination of widely promoted recipes and commercially available products indicates that lactation cookies contain highly variable combinations and quantities of ingredients, including oats, brewer’s yeast and flaxseed.’, and line 359 regarding lactation cookies; ‘Lactation cookies were provided as one of ten listed galactagogues that women could choose from. However participants were not provided with a definition of lactation cookies nor a pre-defined list of ingredients. As such, our survey did not account for possible variations in ingredients between different lactation cookies, and there is likely to be some crossover with other galactagogues listed in the survey, particularly brewer’s yeast which is one of the most common ingredients in lactation cookies.’

6. Lines 244 -248: Perhaps an emphasis on the need for properly conducted and properly described randomized controlled studies could be added after the call for future research? The main reason why there are extremely limited evidence on galactagogue efficacy is not because studies have not been done (there are over 100 studies as of year 2020), but there were problems with the research methods used (many were just observational studies) and the way the research was reported/described which prevented us from drawing firm findings. Another huge weakness of most studies is the lack of exploration of potential side effects, as well as long-term breastfeeding outcomes. (Lines 67-68 mentioned that “The review found uncertain evidence that galactagogues improve ……. longer-term breastfeeding outcomes” The lack of evidence here indeed was because there were no studies exploring this outcome.)

Response 6: An amendment has been made to line 388-391; ‘Overall, our findings highlight the need for further high-quality research, particularly appropriately powered randomized controlled trials, to generate robust evidence about the efficacy and safety of galactagogues to support evidence-based strategies to improve breastfeeding outcomes.’

7. Lines 268-270: Would the authors have data on which ethnic group used which galactagogue? (eg was ginger more popular with the Chinese?) It would be interesting it this data was available.

Response 7: Unfortunately our survey did not include questions about ethnicity, so we cannot address this question.

Reviewer #2: Thank you for the opportunity to review this interesting and well-written manuscript. It reports important findings resulting from a technically sound piece of scientific research. I have provided some minor suggestions and comments for consideration.

Introduction

1. Line 48: Please consider minor revision of the important first sentence with respect to the word "benefit".

Language used to describe lactation can have unintended interpretations. As noted in the third sentence, lactation is a phase of the reproductive cycle that statistics show is not functioning to recommendations. The description of breastfeeding as conferring “benefits” is problematic because it can be interpreted to imply that lactation is a beneficial optional extra, rather than a phase of the reproductive cycle that is the biologic norm (for example, we don’t typically talk about the “benefits” of effective heart function). Health outcomes are poorer for both mother and infant if this biologic norm is not sustained to recommendations.

Line 49: For similar reasons, please also consider changing the word “promote” to “recommend”.

Response 1: Line 51 has been amended to reflect your comments; ‘Breastfeeding is widely recognised to promote lifelong health for both the mother and infant’

Line 53 has been amended; ‘International recommendations are exclusive breastfeeding…’

2. Line 60: The reference cited does not cite evidence for association of correct positioning and latch with improvement in milk synthesis. Suggest alternative of ensuring maximal breast drainage (such as via increased breastfeed frequency +/- hand expression and/or pumping) as an evidence-based example of a strategy that increases milk synthesis.

Dewey KG, Lönnerdal B. Infant self‐regulation of breast milk intake. Acta Paediatrica. 1986;75(6):893-8.

Daly SE, Hartmann PE. Infant demand and milk supply. Part 2: The short-term control of milk synthesis in lactating women. Journal of Human Lactation. 1995;11(1):27-37.

Morton J, Hall JY, Wong RJ, Thairu L, Benitz WE, Rhine WD. Combining hand techniques with electric pumping increases milk production in mothers of preterm infants. Journal of perinatology : official journal of the California Perinatal Association. 2009;29(11):757-64.

Response 2: The Morton et al 2009 reference has been added to line 64 references.

3. Line 62: Breast milk supply includes consideration of both maternal milk synthesis and transfer of milk to the infant via breastfeeding or breast milk feeding. Suggest replacement of “supply” with “synthesis” as galactogogues only have the possibility of affecting maternal synthesis.

Response 3: The reviewer raises an interesting point. We acknowledge there is no universally accepted definition of galactagogues. In light of the comment we have changed the term ‘supply’ to ‘production’. Changes have been made to line 22; ‘substances thought to increase breast milk production’ and 66; ‘galactagogues – the term used to describe substances thought to promote or increase breast milk production’.

Methods

4. Inclusion of the survey as an appendix or supplement would be very helpful.

Response 4: As above, the survey will be included as a supporting file.

The following has been added at line 134; ‘The complete survey is available as a supporting file (SI File 1).’ And a copy of the survey will be uploaded as a supporting file.

Results

5. Table 2: One bracket missing (Fennel; child’s age at survey 12+months)

Response 5: This has been amended in the table.

6. Line 199: Some text missing

Response 6: Missing text has been addressed, as per the Editor’s comments;

The following amendment has been made to line 218-220, where the underlined text has been added; ‘The proportion of women reporting commencing individual galactagogues within the first seven days postpartum, ranged from 4 to 67%.’

7. Figures 2 & 5: For me, the inclusion of colour assists with interpretation of these figures, however, perhaps consider ensuring that colour selection is colourblind-friendly.

Response 7: Figure 2 and 5 have been updated to a colourblind friendly scheme.

Discussion

8. Line 240: Objectively, this study is surveying the experience relating to galactogogue use during lactation function. Suggest deletion of “experience” descriptor for lactation.

Response 8: This has been amended to remove the term ‘experience’.

9. General comments for consideration, but not essential for inclusion:

These findings suggest none of the galactogogues are being used in a way that meets minimum quality use of medicine principles for safety and efficacy.

First, there is the lack of appropriate diagnosis to determine whether maternal concerns regarding lactation insufficiency are actual or just perceived and, if actual, to investigate the cause.

If lactation insufficiency is actual, this can be caused by a number of factors, including infant factors resulting in ineffective milk removal that subsequently cause down-regulation of milk synthesis (as stated in the introduction). This is of course further complicated by the lack of objective tests to assess milk production available in routine clinical practice.

Second, there is generally poor or absent evidence for understanding of galactogogue mechanism of action. Even domperidone, where the mechanism is known, is presumably commenced without investigation to determine whether low plasma prolactin is the cause of lactation insufficiency. Further, interpretation of plasma prolactin measurement itself is complicated by the absence of reference ranges for plasma prolactin in lactating women.

How concerning that maternal galactogogue use is so prevalent given that the cause (if lactation insufficiency is actually present) may not even be due to any disruption of maternal physiology, thus rendering the galactogogue without rationale for use and giving greater weight to any incidence of adverse effects. Clearly, women are worried about the adequacy of their breastmilk production and better strategies need to be developed to deliver effective support.

Well done, a thought-provoking study.

Response 9:

An amendment has been made to line 276 ‘discontinuing breastfeeding due to concerns about their milk supply. It is uncertain whether concerns related to breast milk supply were real or perceived, determining which has been often recognised as a common challenge within clinical practice settings (6).’

An amendment has been made in the concluding remarks to reflect some of the general comments above; ‘Overall, our findings highlight the need for further high-quality research, particularly appropriately powered randomized controlled trials, to generate robust evidence about the efficacy and safety of galactagogues to support evidence-based strategies to improve breastfeeding outcomes.’

Some of the comments above are also reflected in lines 333-339; ‘The fact that 1 in 6 respondents started using various galactagogues within the first seven days postpartum raises potential concerns, particularly given the challenge of assessing the adequacy of breast milk production in the early postpartum period (34, 35). These findings may indicate that women may be turning to galactagogues prophylactically (without actually having low breast milk supply) or using them as early treatments before trying non-pharmacological strategies. While 71% of women reported seeing a lactation consultant, we do not know when this occurred relative to the commencement of galactagogues.’

Thank you again for considering our revised manuscript.

Yours sincerely

On behalf of the authors

Luke

Attachment

Submitted filename: PLOS ONE Response to Reviewers_v1.docx

Decision Letter 1

Jane Anne Scott

21 Jun 2021

Use and experiences of galactagogues while breastfeeding among Australian women

PONE-D-21-14565R1

Dear Dr. Grzeskowiak,

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.

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Kind regards,

Jane Anne Scott, PhD, MPH Grad Dip Dietetics, BSc

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Acceptance letter

Jane Anne Scott

24 Jun 2021

PONE-D-21-14565R1

Use and experiences of galactagogues while breastfeeding among Australian women

Dear Dr. Grzeskowiak:

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.

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on behalf of

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Associated Data

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

    Supplementary Materials

    S1 File. Boosting breast milk supply survey.

    All survey questions asked regarding women’s use and experiences with substances to boost breast milk supply.

    (PDF)

    Attachment

    Submitted filename: PLOS ONE Response to Reviewers_v1.docx

    Data Availability Statement

    Data cannot be shared publicly because the ethics committee restricts secondary use of the data currently. Data are available from The University of Adelaide Human Research Ethics Committee (contact T: +61 8 8313 5137 | F: +61 8 8313 3700 | research.services@adelaide.edu.au) for researchers who meet the criteria for access to confidential data.


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