Abstract
Objective:
This study aimed to investigate the effects of white noise combined with breastfeeding guidance on the exclusive breastfeeding success rate, anxiety status, and lactation function in primiparous women with delayed lactation onset; neonatal stress levels; and infants’ physical development.
Methods:
A retrospective study was conducted on 120 primiparous women with delayed lactation onset admitted to Zhejiang Hospital from January 2023 to June 2024. The women were divided into a combination group (n = 60; conventional breastfeeding guidance + white noise measure) and a conventional group (n = 60; only conventional breastfeeding guidance), with a 4-week nursing period for both groups. The related indicators were compared between the two groups, including exclusive breastfeeding rate, LATCH (Latch, Audible swallowing, Type of nipple, Comfort, Hold/Positioning) score, self-rating anxiety scale (SAS) score, lactation indices, neonatal stress scale (NSS) score, and infant growth.
Results:
After nursing, the combination group had significantly higher exclusive breastfeeding rate (P = 0.009) and LATCH score, lower SAS score, shorter lactation onset, and greater residual milk volume than the conventional group (all P < 0.001 except for the breastfeeding rate). The combination group had significantly lower neonatal stress scores and greater grains in weight, length, and head circumference at 4 weeks (all P < 0.001). The combined intervention independently predicted exclusive breastfeeding success (OR = 2.68, 95% CI 1.25–5.76) and was associated with lower SAS (β = −7.28, P = 0.002), lower NSS scores (β = −2.45, P < 0.001), and shorter lactation onset (β = −10.25, P < 0.001).
Conclusion:
White noise combined with breastfeeding guidance can effectively improve the exclusive breastfeeding success rate and lactation function of primiparous women with delayed lactation onset, alleviate maternal anxiety, reduce neonatal stress levels, and promote infant physical development.
Keywords: acoustic stimulation, anxiety, breast feeding, lactation, parity, postpartum period
KEY MESSAGES
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(1)
Combining white noise with conventional breastfeeding guidance significantly improves the exclusive breastfeeding success rate (71.67% versus 48.33%) in primiparous women with delayed lactation.
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(2)
The combined intervention effectively alleviates maternal anxiety (reduced SAS scores) and enhances lactation function (shortened lactation onset time and increased post-breastfeeding residual milk volume).
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(3)
Neonatal stress levels are markedly reduced, and infant physical development (weight gain, length growth, and head circumference growth) is promoted by the intervention.
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(4)
This nonpharmacological, easy-to-implement strategy provides a comprehensive solution for delayed lactation, with dual benefits for maternal and infant health, and is worthy of clinical promotion.
INTRODUCTION
Delayed lactation onset affects 25–40% of primiparous women, primarily because of hormonal fluctuations, inadequate breastfeeding skills, and psychological anxiety.[1,2] First-time mothers are particularly susceptible.[3] Psychological stress suppresses prolactin secretion via neuroendocrine mechanisms, thereby reducing milk production and creating a vicious cycle.[4] Exclusive breastfeeding benefits infant immunity, intestinal flora and maternal health (reducing uterine bleeding and breast cancer risk). However, delayed lactation reduces exclusive breastfeeding success and exacerbates anxiety.[5]
Current clinical care focuses on conventional breastfeeding guidance (feeding positions, latch techniques, diet, rest, and psychological counseling).[6] White noise, an acoustically uniform signal with equal intensity across all audible frequencies, has been investigated for its anxiolytic and stress-reducing effects in clinical settings. By providing a constant, predictable auditory background, white noise can mask disruptive environmental sounds and may promote autonomic nervous system stability, thereby reducing sympathetic arousal and cortisol secretion.[7,8] Preliminary evidence suggests that white noise may improve breastfeeding outcomes by alleviating maternal anxiety and enhancing infant calmness during feeding. However, its value for delayed lactation remains underexplored.[9,10,11] The present study evaluated the effects of white noise combined with breastfeeding guidance on exclusive breastfeeding success, anxiety, lactation function, neonatal stress, and infant physical development in primiparous women with delayed lactation onset.
MATERIALS AND METHODS
General Information
This retrospective cohort study was conducted in the Department of Gynaecology and Obstetrics at Zhejiang Hospital. Data were extracted from the hospital’s electronic medical record system. The sample size was calculated on the basis of the effect size (OR = 2.58) reported in a previous similar study on white noise and breastfeeding outcomes.[12] Using PASS software with a two-sided significance level (α) of 0.05, a test power (1 − β) of 80%, and an estimated control-group exclusive breastfeeding rate of 45% (derived from previous data on delayed lactation populations), the minimum required sample size was found to be 52 participants per group. This number confirmed that the sample size was sufficient for this study. A total of 158 primiparous women with delayed lactation onset were assessed for eligibility between January 2023 and June 2024. Among them, 12 were excluded due to pregnancy complications, nine due to breast diseases, eight due to neonatal abnormalities requiring special feeding, and nine due to incomplete data. Ultimately, 120 cases were enrolled in the final analysis, with 60 cases in the white noise combination group and 60 cases in the conventional care group [Figure 1]. No cases were lost to follow-up during the 4-week nursing period. No statistically significant differences were found in the baseline characteristics between the included and excluded groups (all P > 0.05). The participants were grouped retrospectively in accordance with the clinical treatment measures recorded in electronic medical records. No randomization method was adopted in the grouping process, consistent with the retrospective study design.
Figure 1.
Diagram of patient inclusion process.
The inclusion criteria were as follows: (1) primiparous women aged 20–35 years; (2) gestational age of 37–42 weeks with full-term singleton delivery; (3) meeting the diagnostic criteria for delayed lactation onset (no spontaneous lactation within 48 h postpartum or milk yield < 50 mL/24 h, accompanied by infant crying after feeding and weight loss > 5%)[13]; (4) no history of hearing impairment or mental illness; and (5) voluntary participation in the study with signed informed consent. The exclusion criteria were as follows: (1) pregnancy complications such as gestational diabetes or hypertension; (2) the presence of breast diseases (e.g., mastitis or mammary gland hyperplasia); (3) neonatal asphyxia, congenital malformations, or other conditions requiring special feeding; and (4) withdrawal from the study during the care period due to personal reasons. This study was approved by the Ethics Review Committee of Zhejiang Hospital (Approval No. ZJHIRB-2025-027K). This study was conducted in accordance with the ethical standards of the Declaration of Helsinki. All participants provided written informed consent prior to their inclusion in the study.
Nursing Measures
The nursing measures for both groups were based on the clinical nursing records in the medical database. The nursing cycle recorded in the medical records was 4 weeks for all patients, starting within 24 h after delivery and lasting until postpartum day 28.
All observational indices were assessed before care (within 24 h postpartum) and after care (on postpartum day 7) to evaluate the treatment effects. The specific assessment criteria for each index are as follows:
Conventional Care Group: Conventional Breastfeeding Guidance
The conventional care group received standard breastfeeding guidance during hospitalization and follow-up, including breastfeeding technique guidance, diet and lifestyle guidance, and psychological counseling [Table 1]:
Table 1.
Nursing and white noise treatment protocol (schematic diagram above)
| Treatment content | Conventional care group (n = 60) | White noise combination group (n = 60) |
|---|---|---|
| Core treatment | Conventional breastfeeding guidance (4 weeks) | ✓ Conventional breastfeeding guidance (same as the left, 4 weeks) ✓ Additional white noise measure (during breastfeeding, 4 weeks) |
| Breastfeeding guidance | (1) Technique guidance (30 min/d) (2) Diet/lifestyle guidance (2) Psychological counselling (20 min, two times a week) |
Consistent with the left |
| White noise neasure | None | (1) Device: HN-2022 (500–1500 Hz) (2) Timing: 30 min before breastfeeding to the end (30–45 min/session, three times/d) (3) Intensity: 40–60 dB (near mother’s ear) |
| Nursing cycle | From 24 h postpartum to 4 weeks postpartum | Consistent with the left |
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(a)
Breastfeeding technique guidance: This guidance was provided once daily for 30 min per session. It involved demonstrating feeding positions (e.g., cradle hold and side-lying position), teaching proper infant latch techniques (latching onto the areola rather than the nipple), and instructing mothers to observe signs of effective feeding in the infant (such as milk leakage at the corners of the mouth or audible swallowing sounds).
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(b)
Diet and lifestyle guidance: The mothers were advised to adopt a diet rich in protein (e.g., fish, eggs, and milk) and dietary fiber while avoiding spicy and stimulating foods. A daily water intake of 2000–2500 mL was recommended. They were also instructed to ensure 7 or 8 h of sleep per day and to avoid excessive fatigue.
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(c)
Psychological counseling: This counseling was conducted twice weekly for 20 min per session. It involved actively listening to the mothers’ concerns and explaining the physiological mechanisms of lactation to alleviate their anxiety.
White Noise Combination Group: Conventional Breastfeeding Guidance + White Noise Measure
The white noise combination group received the same conventional breastfeeding guidance as the conventional care group, and an additional white noise measure was implemented during breastfeeding (Table 1):
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(a)
White noise device: A professional medical white noise apparatus (model: HN-2022, Hengnuo Medical Instrument Co., Ltd., Jiangsu, China; frequency range: 500–1500 Hz, adjustable sound level) was used.
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(b)
Playback parameters: White noise playback commenced 30 min before the start of each breastfeeding session and continued until its conclusion (lasting 30–45 min per session). It was performed three times daily, corresponding to morning, midday, and evening feeding times.
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(c)
Intensity control: The sound pressure level near the mother’s ear was monitored using a sound level meter (model: TES-1350A, TES Electronic Industrial Co., Ltd., Taiwan, China) and maintained within the range of 40–60 dB. During the white noise treatment, strict background noise control was implemented in the mother–infant room: all unrelated electronic equipment (e.g., TV and intercom) was turned off, medical staff reduced walking and talking volume, and the background noise level was maintained at ≤30 dB (monitored using the same sound level meter) to avoid interference with the white noise treatment.
Observation Indices
Breastfeeding Success Rate
Primary outcome measure: The exclusive breastfeeding rate was assessed on postpartum day 7. Exclusive breastfeeding was defined as the infant receiving no liquids or solid foods other than medications, vitamins, or minerals.
Secondary outcome measure: The Latch, Audible swallowing, Type of nipple, Comfort, Hold/Positioning (LATCH) breastfeeding assessment tool was used for evaluation before care (within 24 h postpartum) and after care (on postpartum day 7).[14] This tool scores five aspects: infant latch, audible swallowing, mother’s nipple type, mother’s comfort, and hold/positioning. The total score ranges from 0 to 10, with higher scores indicating a smoother feeding process. The tool’s content validity index (CVI) was 0.92.
Anxiety Status
The self-rating anxiety scale (SAS) was used to assess maternal anxiety before care and after care (on postpartum day 7).[15] This scale comprises 20 items, with total scores ranging from 20 to 80. A higher score indicates a more severe level of anxiety. The Cronbach’s α coefficient was 0.88, and the criterion-related validity was r = 0.78 (compared with Hamilton Anxiety Rating Scale).
Lactation Status
Time-to-lactogenesis onset: The time interval (in hours) from delivery to the maternal perception of remarkable breast fullness and a noticeable sensation of milk “coming in” was recorded.
Post-breastfeeding residual milk volume (indirect lactation function indicator): On days 3 and 7 after care initiation, a standard breast pump (Medela AG, Basel, Switzerland) was used to completely empty both breasts within 1 h after a fixed-time direct breastfeeding session. The milk volume was measured and recorded using a graduated cylinder (Glass Instrument Factory of Nanjing University, Jiangsu, China). This indicator reflects the residual milk reserve in the breasts after breastfeeding and the efficiency of milk expression, serving as an indirect assessment of lactation function improvement (note: due to the condition of delayed lactation and insufficient milk supply in the research subjects, this volume does not represent the total daily milk output but reflects the dynamic changes in lactation capacity during the care period).
Breast fullness: Breast fullness was assessed by trained nursing staff on days 3 and 7 after nursing using a 4-point grading scale (4-PGS).[16] Grade 0: no breast fullness, soft and flaccid; grade 1: mild fullness and slight firmness without obvious swelling; grade 2: moderate fullness, firm but not tender, and no skin tension; grade 3: severe fullness, hard texture, and obvious skin tension. “Good breast fullness” was defined as grade 2 or 3, and the proportion of subjects meeting this standard was calculated.
Breast-distending pain degree: The degree of breast-distending pain was evaluated by the mothers using the numerical rating scale (NRS) on days 3 and 7 after nursing.[17] The scale ranges from 0 to 10 points, where 0 points = no pain, 1–3 points = mild pain (bearable, does not affect breastfeeding), 4–6 points = moderate pain (occasionally affects breastfeeding), and 7–10 points = severe pain (unbearable, unable to breastfeed). The score reported is the mother’s self-rated score at the time of assessment. NRS had a CVI = 0.95 and an ICC = 0.91.
Neonatal-Related Indices
Neonatal stress level: The neonatal stress scale (NSS) was used for assessment before care and after care (on postpartum day 7).[18] This scale includes five core dimensions: behavioral state (such as alert, drowsy, or crying); muscle tone (relaxed, tense, or rigid); respiratory pattern (regular, irregular, or tachypnea); facial expression (calm, frown, or grimace); and limb movement (gentle, restless, or thrashing). Each dimension is rated on a 3-point scale (0 = no stress, 1 = mild stress and 2 = severe stress), with total scores ranging from 0 to 10. A higher total score indicates a higher level of neonatal stress. The scale had a Cronbach’s α coefficient = 0.83, ICC = 0.87, and CVI = 0.90.
Physical development: Neonatal weight, length, and head circumference were recorded at birth and 4 weeks of age. The increments were calculated.
Statistical Analysis
Statistical analysis was performed using SPSS (IBM Corporation, New York, USA) software (version 25.0). Continuous data were tested for normal distribution by using the Shapiro–Wilk test, and they are presented as mean ± standard deviation (x̄±s). Inter-group comparisons were conducted using an independent sample t-test, and intra-group comparisons before and after care were performed using a paired t-test. Categorical data are presented as numbers (percentage) [n (%)], and comparisons between groups were conducted using chi-square (χ2) test. Binary logistic regression analysis was used to identify independent protective factors for exclusive breastfeeding success, with exclusive breastfeeding success (1 = success and 0 = failure) as the dependent variable and treatment mode (1 = combination group and 0 = conventional group), age, mode of delivery, and educational level as independent variables. Multiple linear regression analysis was applied to analyze independent influencing factors for maternal SAS score, NSS score, and lactation onset time, with the above indicators as dependent variables and treatment mode (1 = combination group and 0 = conventional group) as the independent variable [adjusted for age and postpartum body mass index (BMI)]. The selection of independent variables for the regression models was based on clinical relevance and prior literature identifying these factors as potential confounders in lactation and postpartum psychological outcomes. Variables with baseline differences approaching significance (P < 0.10) or established clinical importance were included regardless of univariate screening results. All regression analysis results were reported with effect size (OR/β) and its 95% confidence interval (95% CI). A two-tailed P-value <0.05 was considered statistically significant.
RESULTS
Comparison of Baseline Characteristics of Subjects
A total of 120 primiparous women with delayed lactation were finally included in the study. No statistically significant differences were found in the basic demographic and clinical characteristics (both P >0.05), confirming comparability between the two groups [Table 2].
Table 2.
Comparison of baseline characteristics of primiparous women with delayed lactation between two groups
| Characteristic | White noise combination group (n = 60) | Routine nursing group (n = 60) | t/χ2 value | P-value |
|---|---|---|---|---|
| Age (years) | 27.46 ± 3.17 | 27.83 ± 3.63 | 0.595 | 0.553 |
| Gestational weeks | 38.92 ± 1.15 | 39.16 ± 1.08 | 1.178 | 0.241 |
| Postpartum BMI (kg/m2) | 24.12 ± 2.35 | 24.36 ± 2.51 | 0.541 | 0.590 |
| Time of delayed lactation diagnosis (h postpartum) | 18.25 ± 4.12 | 18.58 ± 4.36 | 0.426 | 0.671 |
| Neonatal body weight (g) | 3256.75 ± 312.48 | 3198.63 ± 298.74 | 1.041 | 0.300 |
| Mode of delivery [n (%)] | 0.315 | 0.575 | ||
| Vaginal delivery | 38 (63.33) | 35 (58.33) | ||
| Caesarean section | 22 (36.67) | 25 (41.67) | ||
| Educational level [n (%)] | 0.926 | 0.336 | ||
| High school or below | 18 (30.00) | 23 (38.33) | ||
| College or above | 42 (70.00) | 37 (61.67) |
Note: BMI = body mass index. No statistically significant differences were found between the two groups in all indicators (all P > 0.05).
Comparison of Breastfeeding Success Rate and Anxiety Before and After Nursing
Before nursing, no significant differences were observed between the two groups in terms of LATCH score, SAS score, and exclusive breastfeeding rate (P > 0.05). After nursing, the LATCH score (6.58 ± 1.02) and exclusive breastfeeding rate (71.67%) in the white noise combination group were significantly higher than those in the conventional care group (5.12 ± 1.24 and 48.33%), whereas the anxiety score (42.36 ± 4.82) was significantly lower than that in the conventional care group (49.75 ± 5.16). All differences were statistically significant (P < 0.001) [Table 3].
Table 3.
Comparison of breastfeeding success rate and anxiety state of parturients in two groups before and after nursing
| Group | n | LATCH score |
SAS score |
Exclusive breastfeeding rate [n (%)] | ||
|---|---|---|---|---|---|---|
| Pre-nursing | Post-nursing | Pre-nursing | Post-nursing | |||
| White noise combination group | 60 | 3.45 ± 0.86 | 6.58 ± 1.02* | 52.34 ± 5.67 | 42.36 ± 4.82* | 43 (71.67) |
| Routine nursing group | 60 | 3.52 ± 0.91 | 5.12 ± 1.24* | 51.87 ± 5.92 | 49.75 ± 5.16* | 29 (48.33) |
| t /χ2 value | 0.433 | 7.044 | 0.444 | 8.107 | 6.806 | |
| P-value | 0.666 | < 0.001 | 0.658 | < 0.001 | 0.009 | |
Note: LATCH, Latch, Audible swallowing, Type of nipple, Comfort, Hold/Positioning; SAS, Self-Rating Anxiety Scale. *P < 0.001 compared with that in the same group before nursing.
Comparison of Neonatal-Related Indicators
The comparisons of stress levels and physical development indicators of neonates between the two groups before and after nursing are shown in Table 4. After nursing, the stress level score of neonates in the white noise combination group was (3.36 ± 0.82), significantly lower than that in the routine nursing group (5.88 ± 1.06, P < 0.05). In terms of physical development, the neonatal weight gain, body length gain, and head circumference gain in the white noise combination group were significantly superior to those in the conventional care group at 4 weeks after nursing (P < 0.001).
Table 4.
Comparison of neonatal related indicators between the two groups
| Group | n | Neonatal stress score (score) |
Body weight gain (kg) | Length growth (cm) | Head circumference growth (cm) | |
|---|---|---|---|---|---|---|
| Pre-nursing | Post-nursing | |||||
| White noise combination group | 60 | 7.62 ± 1.24 | 3.36 ± 0.82* | 1.86 ± 0.32 | 5.42 ± 0.87 | 3.75 ± 0.64 |
| Routine nursing group | 60 | 7.58 ± 1.31 | 5.88 ± 1.06* | 1.52 ± 0.29 | 4.68 ± 0.79 | 3.32 ± 0.58 |
| t-value | 0.172 | 14.565 | 6.098 | 4.878 | 3.856 | |
| P-value | 0.864 | <0.001 | <0.001 | <0.001 | <0.001 | |
Note: Breast fullness was assessed by a 4-point grading scale. “Good breast fullness” refers to grade 2 or 3. Breast distending pain degree was evaluated using the numerical rating scale (0–10 points). *P < 0.001 compared with that in the same group before nursing.
Comparison of Lactation Conditions Between the Two Groups
As shown in Table 5, the white noise combination group was significantly superior to the conventional nursing group in terms of lactation onset time, daily lactation volume, and breast fullness (P < 0.001, P < 0.001, P < 0.001, P = 0.003, and P < 0.001). The mean lactation onset time was 25.36 ± 5.42 h in the white noise combination group, significantly shorter than the 35.74 ± 6.83 h in the conventional nursing group. On day 7 after nursing, the post-breastfeeding residual milk volume in the white noise combination group was 458.76 ± 65.38 mL, which was significantly higher than that of the conventional care group (365.47 ± 58.92 mL), indicating that the combined nursing was more conducive to improving lactation reserve capacity.
Table 5.
Comparison of lactation conditions of parturients between the two groups
| Group | n | Lactation start time (h) | Post-breastfeeding residual milk volume (mL) |
Good breast fullness [n (%)] | Breast distending pain degree (points) | |
|---|---|---|---|---|---|---|
| 3 day after nursing | 7 day after nursing | |||||
| White noise combination group | 60 | 25.36 ± 5.42 | 185.63 ± 42.57 | 458.76 ± 65.38* | 52 (86.67) | 2.15 ± 0.68 |
| Routine nursing group | 60 | 35.74 ± 6.83 | 152.84 ± 38.76 | 365.47 ± 58.92* | 38 (63.33) | 3.42 ± 0.87 |
| t /χ2 value | 9.221 | 4.412 | 8.211 | 8.711 | 8.909 | |
| P-value | <0.001 | <0.001 | <0.001 | 0.003 | <0.001 | |
Note: Breast fullness was assessed by a 4-point grading scale. “Good breast fullness” refers to grade 2 or 3. Breast distending pain degree was evaluated using the numerical rating scale (0–10 points). *P < 0.001 compared with that in the same group before nursing.
Regression Analysis of Influencing Factors for Treatment Effects
Binary logistic and multiple linear regression analyses were performed to control for confounding factors (age, mode of delivery, educational level, and postpartum BMI) and further confirm the treatment effect of white noise combined with breastfeeding guidance.
The results of binary logistic regression analysis showed that white noise combined with breastfeeding guidance was an independent protective factor for the success of exclusive breastfeeding (OR = 2.68, 95% CI: 1.25–5.76, P = 0.011).
As shown in Table 6, the results of multiple linear regression analysis showed that the combination treatment was an independent factor for reducing maternal SAS score (β = −7.28, 95% CI: from −10.35 to −4.21, P = 0.002), reducing NSS score (β = −2.45, 95% CI: from −3.12 to −1.78, P < 0.001), and shortening lactation onset time (β = −10.25, 95% CI: from −12.68 to −7.82, P < 0.001.
Table 6.
Regression analysis results of influencing factors for treatment effects
| Analysis type | Dependent variable | Independent variable | Effect size | 95% CI | P-value | Model fitting index |
|---|---|---|---|---|---|---|
| Binary logistic regression | Exclusive breastfeeding success (1 = success, 0 = failure) | Treatment mode (combination group = 1) | OR = 2.68 | 1.25–5.76 | 0.011 | Hosmer–Lemeshow χ2 = 6.25, P = 0.512 |
| Age (years) | OR = 1.02 | 0.95–1.09 | 0.635 | |||
| Mode of delivery (vaginal = 1) | OR = 1.15 | 0.52–2.56 | 0.728 | |||
| Educational level (college or above = 1) | OR = 1.36 | 0.61–3.05 | 0.452 | |||
| Multiple linear regression | Maternal SAS score | Treatment mode (combination group = 1) | B = −7.28 | From −10.35 to −4.21 | 0.002 | R2 = 0.385, F = 18.25, P < 0.001 |
| Age (years) | β = 0.12 | From −0.25 to 0.49 | 0.526 | |||
| Postpartum BMI (kg/m2) | β = 0.36 | From −0.18 to 0.90 | 0.192 | |||
| NSS score | Treatment mode (combination group = 1) | β = −2.45 | From −3.12 to −1.78 | < 0.001 | R2 = 0.452, F = 25.68, P < 0.001 | |
| Age (years) | β = 0.08 | From −0.32 to 0.48 | 0.695 | |||
| Postpartum BMI (kg/m2) | β = 0.21 | From −0.25 to 0.67 | 0.368 | |||
| Lactation onset time (h) | Treatment mode (combination group = 1) | β = −10.25 | From −12.68 to −7.82 | <0.001 | R2 = 0.426, F = 22.35, P < 0.001 | |
| Age (years) | β = 0.25 | From −0.18 to 0.68 | 0.256 | |||
| Postpartum BMI (kg/m2) | β = 0.42 | From −0.15 to 0.99 | 0.148 |
Note: SAS, self-rating anxiety scale; NSS; neonatal stress scale; BMI, body mass index; OR, odds ratio; β, regression coefficient; 95% CI, 95% confidence interval; h, hour.
DISCUSSION
Delayed lactation onset is a common postpartum complication among primiparous women, with an incidence rate of 25–40%. It not only reduces the exclusive breastfeeding rate but also exacerbates maternal anxiety, creating a vicious cycle detrimental to maternal and infant health.[19] This study adopted a retrospective cohort study design to analyze the efficacy of white noise combined with breastfeeding guidance in primiparous women with delayed lactation onset. The results demonstrated that combined nursing was associated with significantly higher exclusive breastfeeding success rates and LATCH scores, as well as lower maternal anxiety levels than conventional care.
The finding that adding white noise to conventional breastfeeding guidance significantly improved LATCH scores and the exclusive breastfeeding rate suggests that white noise exerts regulatory effects on the maternal neuroendocrine system and the lactation process. The underlying mechanism may involve the white noise used in this study, which effectively masks environmental disturbance signals (e.g., neonatal crying and ward noise) that may induce maternal stress.[20] A growing body of auditory treatment research has confirmed the positive regulatory effects of moderate-intensity white noise on the maternal and neonatal autonomic nervous system, with consistent conclusions on its anxiolytic and stress-reducing effects in perinatal care. For example, Liao et al.[21] found that white noise (50–55 dB) considerably increased oxygen saturation and promoted weight gain in preterm infants, indicating enhanced physiological stability through autonomic regulation. Additionally, a comprehensive review by Öz and Demirci[22] concluded that white noise exerted a suppressive effect on the sympathetic nervous system, leading to decreased levels of stress-related catecholamines and reduced physiological stress indicators, such as heart rate and blood pressure, in mothers and newborns. Previous research has confirmed that moderate-intensity white noise (40–60 dB) can reduce sympathetic nervous system activity and enhance parasympathetic tone, thereby decreasing the secretion of stress hormones, such as cortisol.[23] In the present study, the post-nursing SAS score in the combination group was significantly lower than that in the conventional guidance group, indicating that reduced cortisol levels may attenuate the inhibitory effect of stress on prolactin secretion, thereby creating a favorable hormonal environment for milk production.[24] Furthermore, white noise may enhance the efficacy of breastfeeding guidance by improving maternal comfort and operational coordination. While the conventional guidance group received training on feeding positions and latch techniques, maternal anxiety may lead to muscle tension and reduced motor coordination, thereby hindering the full application of these skills.[25] In the combination group, the autonomic nervous system balance induced by white noise helped mothers maintain a relaxed state, thereby contributing to higher LATCH scores. The LATCH scale assesses the breastfeeding process across five dimensions, including infant latch and maternal breast comfort. Higher scores indicate smoother mother–infant feeding interactions, thereby increasing the likelihood of exclusive breastfeeding success.[26]
The integration of white noise into breastfeeding care offers a practical, nonpharmacological adjunct to conventional lactation support. This combined approach addresses the interplay between maternal anxiety and lactation physiology by creating a calmer feeding environment, which may facilitate more effective breastfeeding behaviors.[27] The observed improvements in LATCH scores and exclusive breastfeeding rates suggest that this low-cost intervention can be readily implemented in postpartum wards or community settings without requiring extensive resources or specialized training.[28,29] While the precise acoustic parameters warrant further investigation, the present findings support the use of white noise as a safe and accessible strategy to enhance breastfeeding outcomes in primiparous women experiencing delayed lactation onset.
The findings also revealed that the combination of white noise not only reduced neonatal stress levels but also promoted infant physical development. The mechanism for stress reduction may lie in the acoustic similarity between white noise and the intrauterine. The fetus adapts to continuous low-frequency noises in utero, such as maternal blood flow and intestinal sounds. By activating the auditory–limbic pathway, postpartum white noise can mimic these background sounds (e.g., maternal heartbeat, blood flow, and amniotic fluid movement), producing a calming effect and improving neonatal sucking behavior. Reduced neonatal crying not only decreases maternal caregiving burden but also helps infants maintain a calmer state during breastfeeding, enhancing latch stability and milk intake efficiency and thus forming a positive feedback loop. Mohseni et al.[30] conducted a clinical trial on premature infants under non-invasive ventilation and found that white noise significantly reduced behavioral responses associated with stress, with the white noise group showing lower stress scores than the sound-reduction group. In a systematic review and network meta-analysis of 28 studies involving 2624 infants, Ding et al.[31] demonstrated that white noise was the most effective intervention for reducing procedural pain (probability of being best: 90.6%) and enhanced controlled heart rate increases during painful procedures. In a meta-analysis of eight randomized controlled trials (RCTs), Zhang et al.[32] confirmed that white noise significantly reduced pain levels, heart rate, and respiratory rate while promoting weight gain in preterm infants. Kim et al.[33] reported that during heel puncture, premature infants in the white noise group had significantly lower pain responses and heart rates, as well as higher oxygen saturation than controls. Lin et al.[34] found that, in surgical neonates, white noise intervention significantly reduced pain scores and salivary cortisol levels, indicating a blunted stress response. Göktürk et al.[29] demonstrated that playing white noise before, during, and after nasal continuous positive airway pressure application reduced pain and stress levels, heart rate, and crying duration in newborns. Sezici and Yigit[35] found that white noise significantly decreased daily crying time and increased sleep duration in infants with colic, with better outcomes than traditional swinging.
Previous clinical measures for delayed lactation have predominantly focused on physiological aspects (e.g., acupoint massage and dietary adjustments) or singular behavioral guidance, with insufficient attention paid to the interaction between maternal psychology and lactation physiology.[36] The present study innovatively integrated white noise with breastfeeding guidance. The exclusive breastfeeding success rate in the combination group reached 71.67%, confirming a synergistic effect between the two measures. Their combination can comprehensively improve lactation outcomes across multiple dimensions. From the perspective of public health ethics and practical promotion, this combined treatment has remarkable advantages over existing delayed lactation treatments. First, it is a nonpharmacological, noninvasive treatment that avoids the potential risks of drug treatment for lactation (e.g., hormonal drugs affecting maternal and infant health), complying with the principle of “minimally invasive treatment” in perinatal public health ethics. Second, the white noise device used is a professional medical apparatus with simple operation and adjustable parameters. It is suitable for clinical ward application and community postpartum care promotion, with low implementation cost and high scalability and thus in line with the public health goal of “low-cost and high-efficiency health treatment.” Third, the treatment protocol has strict dose control and standardized operation steps, which can be easily popularized among medical staff, thereby avoiding the variability of efficacy caused by nonstandard operations. These characteristics address the potential practical and ethical concerns about the broader promotion of the treatment and verify its feasibility in public health practice. In clinical practice, healthcare providers can refer to the methods used in this study, offering white noise measures during maternal feeding sessions and observing its effect on stress levels and feeding efficacy. Simultaneously, incorporating information about white noise into postpartum health education could improve awareness and acceptance of this nonpharmacological approach among mothers and their families.
In the context of global public health efforts to improve exclusive breastfeeding rates, especially for high-risk populations such as primiparous women with delayed lactation onset, this study provides new evidence-based nonpharmacological treatment strategies. Existing global public health guidelines (e.g., WHO breastfeeding guidelines) emphasize the importance of psychological support for postpartum mothers in improving breastfeeding outcomes, and the white noise treatment in this study is a concrete implementation of these guidelines, which enriches the clinical toolkit for postpartum psychological support in public health practice. The findings of this study also provide a reference for the optimization of acoustic environments in perinatal care settings: public health practice should not only focus on reducing environmental noise but also actively construct a targeted, beneficial acoustic environment for maternal and neonatal health, which represents a new direction for the refinement of perinatal public health management.
This study has several limitations. First, all participants were recruited from a single medical institution, which may limit the generalizability of the findings. Second, this study is a retrospective cohort study rather than an RCT; therefore, the observed associations between white noise combined with breastfeeding guidance and the study outcomes are not causal. The results only reveal the statistical correlations between the treatment and indicators; they cannot confirm a direct causal relationship. Third, the effects of specific parameters, such as sound pressure level and frequency characteristics of white noise, warrant further detailed investigation. Fourth, this study did not implement blinding of assessors or participants. Given that assessments using tools such as the LATCH score, SAS, and NSS involve a degree of subjectivity, the results may be susceptible to assessor bias or participant expectations, representing a potential source of assessment bias. Future research should conduct well-designed RCTs to verify the causal relationship between combined white noise treatment and breastfeeding outcomes in primiparous women with delayed lactation onset. Future public health research can further explore the optimal parameters of white noise treatment for different populations (e.g., Caesarean section versus vaginal delivery primiparas) and the cost-effectiveness of the treatment in community postpartum care settings to provide more detailed evidence for its large-scale public health promotion.
CONCLUSION
This study confirms that the combination of white noise and conventional breastfeeding guidance has a comprehensive, positive effect on primiparous women with delayed lactation onset and their neonates. Compared with conventional breastfeeding guidance alone, the combined nursing not only significantly improves the exclusive breastfeeding success rate and lactation function (shortening lactation onset time and increasing post-breastfeeding residual milk volume) in primiparous women but also effectively alleviates maternal anxiety. It can also reduce neonatal stress levels and promote the physical development of infants.
Availability of Data and Materials
The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request. Due to privacy and ethical restrictions (protection of maternal and neonatal personal health information), the raw data are not publicly accessible.
Author Contributions
NaNa Gu contributed to conceptualizing the study, designing the research protocol, defining core knowledge content, conducting literature retrieval, and preparing the manuscript. XiaoWei Xu was responsible for collecting and sorting study data, performing data and statistical analysis, and providing data support for the research conclusions. Authors read and approved the final manuscript, took public responsibility for appropriate portions of the content, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or completeness of any part of the work were appropriately investigated and resolved.
Ethics Approval and Consent to Participate
This study was approved by the Ethics Review Committee of Zhejiang Hospital (Approval No.: ZJHIRB-2025-027K) and conducted in accordance with the principles of the Declaration of Helsinki. All participating primiparous women were fully informed of the study purpose, intervention procedures, and potential risks and provided written informed consent prior to the extraction of their electronic medical record data. For neonatal-related indicators, consent was also obtained from the maternal guardians.
Conflict of Interests
The authors declare that there are no conflicts of interest.
Acknowledgment
The authors thank all participants and staff involved in the health examinations and data collection.
Funding Statement
This study was supported by the Zhejiang Provincial Medical and Health Science and Technology Projects (Grant No.: 2022491371).
REFERENCES
- 1.Farah E, Barger MK, Klima C, Rossman B, Hershberger P. Impaired lactation: Review of delayed lactogenesis and insufficient lactation. J Midwifery Womens Health. 2021;66:631–640. doi: 10.1111/jmwh.13274. [DOI] [PubMed] [Google Scholar]
- 2.Peng Y, Zhuang K, Huang Y. Incidence and factors influencing delayed onset of lactation: A systematic review and meta-analysis. Int Breastfeed J. 2024;19:59. doi: 10.1186/s13006-024-00666-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Li S, Wupuer T, Hou R. Factors influencing delayed onset of lactogenesis: A scoping review. Int J Gen Med. 2024;17:2311–2326. doi: 10.2147/IJGM.S452108. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Branco J, Manuel AR, Completo S, et al. Prevalence and predictive factors of exclusive breastfeeding in the first six months of life. Acta Med Port. 2023;36:416–423. doi: 10.20344/amp.18692. [DOI] [PubMed] [Google Scholar]
- 5.Liu Q, Lin H. Delayed lactogenesis II in high-risk pregnancies: What should we care. Biol Res Nurs. 2025;27:274–281. doi: 10.1177/10998004241300477. [DOI] [PubMed] [Google Scholar]
- 6.Di X, Ge XL, Wang D. Effect of care intervention with a health education form for breastfeeding on breast distension, pain, and lactation in postpartum mothers. World J Clin Cases. 2024;12:5059–5066. doi: 10.12998/wjcc.v12.i22.5059. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Ekici N, SüzerÖzkan F. Effect of white noise on anxiety levels and breastfeeding success of primiparous mothers having vaginal delivery: A randomized controlled trial. Breastfeed Med. 2024;19:476–482. doi: 10.1089/bfm.2023.0309. [DOI] [PubMed] [Google Scholar]
- 8.Karakuş Selçuk A, Karaarslan D, Ergin E, Salğin E. The effect of white noise and recorded lullaby during breastfeeding on newborn stress, mother’s breastfeeding success, and comfort: A randomized controlled trial. J Pediatr Nurs. 2025;81(e16–e):23. doi: 10.1016/j.pedn.2025.01.008. [DOI] [PubMed] [Google Scholar]
- 9.Nagel EM, Howland MA, Pando C. Maternal psychological distress and lactation and breastfeeding outcomes: A narrative review. Clin Ther. 2022;44:215–227. doi: 10.1016/j.clinthera.2021.11.007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Dewey KG. Maternal and fetal stress are associated with impaired lactogenesis in humans. J Nutr. 2001;131:3012S–3015S. doi: 10.1093/jn/131.11.3012S. [DOI] [PubMed] [Google Scholar]
- 11.Lichnovska R, Dudova K, Rabara A. When your body tells you to not breastfeed—the connivance of oxytocin, prolactin, and dopamine. Int J Mol Sci. 2025;26:5909. doi: 10.3390/ijms26125909. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Negida A, Fahim N. Sample size calculation guide—part 3: how to calculate the sample size for an independent case-control study. Adv J Emerg Med. 2019;3:e20. doi: 10.22114/AJEM.v0i0.138. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Chapman DJ, Pérez-Escamilla R. Maternal perception of the onset of lactation is a valid, public health indicator of lactogenesis stage II. J Nutr. 2000;130:2972–2980. doi: 10.1093/jn/130.12.2972. [DOI] [PubMed] [Google Scholar]
- 14.Rapheal SM, Rajaiah B, Karupanan R, Abiramalatha T, Ramakrishnan S. LATCH score for identification and correction of breastfeeding problems—a prospective observational study. Indian Pediatr. 2023;60:37–40. [PubMed] [Google Scholar]
- 15.Tung VS, Thong NV, Mai NP, et al. Diagnostic value in screening severe depression of the Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, Beck Depression Inventory Scale, and Zung’s Self-Rating Anxiety Scale among patients with recurrent depression disorder. Acta Inform Med. 2023;31:249–253. doi: 10.5455/aim.2023.31.249-253. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Marcellin L, Chantry AA. Allaitement maternel (partie III): complications de l’allaitement—Recommandations pour la pratique clinique [Breastfeeding (part III): Breastfeeding complications—Guidelines for clinical practice] J Gynecol Obstet Biol Reprod (Paris) 2015;44:1084–1090. doi: 10.1016/j.jgyn.2015.09.029. [DOI] [PubMed] [Google Scholar]
- 17.Ferreira-Valente MA, Pais-Ribeiro JL, Jensen MP. Validity of four pain intensity rating scales. Pain. 2011;152:2399–2404. doi: 10.1016/j.pain.2011.07.005. [DOI] [PubMed] [Google Scholar]
- 18.Newnham CA, Inder TE, Milgrom J. Measuring preterm cumulative stressors within the NICU: The Neonatal Infant Stressor Scale. Early Hum Dev. 2009;85:549–555. doi: 10.1016/j.earlhumdev.2009.05.002. [DOI] [PubMed] [Google Scholar]
- 19.Jullien S, Mateescu I, Carai S. Hypogalactia after delivery: A man-made problem. J Glob Health. 2023;13:03053. doi: 10.7189/jogh.13.03053. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Kucukoglu S, Aytekin A, Celebioglu A, Celebi A, Caner I, Maden R. Effect of white noise in relieving vaccination pain in premature infants. Pain Manag Nurs. 2016;17:392–400. doi: 10.1016/j.pmn.2016.08.006. [DOI] [PubMed] [Google Scholar]
- 21.Liao J, Liu G, Xie N, Wang Y, Zhao H, Li M, et al. Mothers’ voices and white noise on premature infants’ physiological reactions in a neonatal intensive care unit: a multi-arm randomized controlled trial. Int J Nurs Stud. 2021;119:103934. doi: 10.1016/j.ijnurstu.2021.103934. [DOI] [PubMed] [Google Scholar]
- 22.Öz T, Demirci N. Applications of white noise in maternal and neonatal care: A comprehensive review on sleep, stress, and pain outcomes. Noise Health. 2025;27:668–675. doi: 10.4103/nah.nah_154_25. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Otlu B, Esenay FI. Use of mothers milk odor and white noise on pain management in preterm infants: A randomized controlled trial. Adv Neonatal Care. 2025;25:28–36. doi: 10.1097/ANC.0000000000001214. [DOI] [PubMed] [Google Scholar]
- 24.Ruzic L, Kalim Assaf G, Vuckovic V, Cigrovski Berkovic M. Hormonal dynamics in response to short-term hypoxia exposure: Cortisol and prolactin regulation as adaptive mechanisms. Cureus. 2024;16:e72703. doi: 10.7759/cureus.72703. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Ulin M, Edokobi N, Ganjineh B, Magann EF, Whitham MD. The impact of environmental and occupational noise on maternal and perinatal pregnancy outcomes. Obstet Gynecol Surv. 2024;79:219–232. doi: 10.1097/OGX.0000000000001262. [DOI] [PubMed] [Google Scholar]
- 26.Livaoglu Say B, Kaya FE, Hatipoglu HU. Effectiveness of combining LATCH and bristol breastfeeding assessment scales in predicting exclusive breastfeeding. Breastfeed Med. 2026;21:202–208. doi: 10.1177/15568253251404483. [DOI] [PubMed] [Google Scholar]
- 27.Münzel T, Sørensen M, Daiber A. Transportation noise pollution and cardiovascular disease. Nat Rev Cardiol. 2021;18:619–636. doi: 10.1038/s41569-021-00532-5. [DOI] [PubMed] [Google Scholar]
- 28.Erol DD, Özalp Gerçeker G. Effects of white noise and therapeutic touch on pain and comfort in newborns during heel lance: A randomized controlled study. Adv Neonatal Care. 2024;24:E79–E87. doi: 10.1097/ANC.0000000000001200. [DOI] [PubMed] [Google Scholar]
- 29.Göktürk G, Karakoç H, Çiftçi A. Effect of white noise during nasal continuous positive airway pressure application on newborn’s pain and stress levels, physiological parameters, and crying durations: a randomized controlled study. J Pediatr Nurs. 2024;78:e330–337. doi: 10.1016/j.pedn.2024.07.022. [DOI] [PubMed] [Google Scholar]
- 30.Mohseni H, Ramezani M, Saki A, Poor-Alizadeh N. Comparison of the effect of the white noise and sound reduction on behavioral responses of premature infants under noninvasive ventilation: A clinical trial. J Perinat Neonatal Nurs. 2026;40:59–67. doi: 10.1097/JPN.0000000000000902. [DOI] [PubMed] [Google Scholar]
- 31.Ding S, Wang Q, Zhang L, et al. Effects of acoustic stimulation on painful procedures in preterm and full-term infants: A systematic review and network meta-analysis. Int J Nurs Stud. 2025;165:105031. doi: 10.1016/j.ijnurstu.2025.105031. [DOI] [PubMed] [Google Scholar]
- 32.Zhang Q, Huo Q, Chen P, Yao W, Ni Z. Effects of white noise on preterm infants in the neonatal intensive care unit: A meta-analysis of randomised controlled trials. Nurs Open. 2024;11:e2094. doi: 10.1002/nop2.2094. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Kim MH, Song JE, Ahn JA, You MA. Effect of white noise on pain response, heart rate, and oxygen saturation during heel puncture in premature infants: A randomized controlled trial. J Perinat Neonatal Nurs. 2024;38:297–305. doi: 10.1097/JPN.0000000000000779. [DOI] [PubMed] [Google Scholar]
- 34.Lin S, Li L, Ren X, et al. Effects of white noise on pain scores and salivary cortisol levels in surgical neonates: a randomized controlled trial. Adv Neonatal Care. 2024;24:291–300. doi: 10.1097/ANC.0000000000001167. [DOI] [PubMed] [Google Scholar]
- 35.Sezici E, Yigit D. Comparison between swinging and playing of white noise among colicky babies: A paired randomised controlled trial. J Clin Nurs. 2018;27:593–600. doi: 10.1111/jocn.13928. [DOI] [PubMed] [Google Scholar]
- 36.Deif R, Burch EM, Azar J, et al. Dysphoric milk ejection reflex: the psychoneurobiology of the breastfeeding experience. Front Glob Womens Health. 2021;2:669826. doi: 10.3389/fgwh.2021.669826. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request. Due to privacy and ethical restrictions (protection of maternal and neonatal personal health information), the raw data are not publicly accessible.