Abstract
Objective:
To evaluate the effects of skin-to-skin contact (SSC) and noise control on noise-induced stress, breastfeeding self-efficacy, and neonatal cortisol regulation.
Methods:
A retrospective study of 182 mother–infant pairs admitted between January 2023 and January 2025 divided into three groups based on perinatal care protocols: Standard group (n = 62) receiving routine care with no noise control, Noise Control group (n = 55) with noise control, and Noise Control + SSC group (n = 65) with both noise control and SSC protocol. Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF), Infant Breastfeeding Assessment Tool (IBFAT), neonatal cortisol levels, heart rate (HR), oxygen saturation (SpO₂), and breastfeeding initiation time were compared.
Results:
Cortisol levels in both neonates and mothers were higher in the Standard group compared to the Noise Control and Noise Control + SSC groups at 24 and 72 h (P < 0.05). The Noise Control + SSC group exhibited lower cortisol levels than the Noise Control group at both timepoints (P < 0.05). Neonatal HR was higher, and SpO₂ was lower in the Standard group compared to the other two groups (P < 0.05). BSES-SF and IBFAT scores were significantly lower in the Standard group (P < 0.05), with longer breastfeeding initiation time and lower exclusive breastfeeding rates at 72h (P < 0.05).
Conclusion:
Noise control and SSC remarkedly reduced noise-induced stress biomarkers, improved short-term breastfeeding self-efficacy, and accelerated lactation initiation. These findings support SSC as a low-cost intervention to buffer perinatal environmental stressors in clinical settings.
Keywords: skin-to-skin contact, breastfeeding, noise, postpartum care, neonatal stress
KEY MESSAGES
-
(1)
SSC and noise management significantly reduced maternal and neonatal stress biomarkers in noise-exposed environments, with cortisol levels approaching those observed under no-noise conditions.
-
(2)
SSC and noise management stabilized neonatal cardiorespiratory function by lowering heart rate and improving oxygen saturation during acute noise exposure.
-
(3)
SSC and noise management enhanced maternal breastfeeding self-efficacy and accelerated lactation initiation in a noise environment.
INTRODUCTION
Breastfeeding provides critical health benefits for both infants and mothers. For infants, it reduces risks of infections, enhances neurodevelopmental outcomes, and lowers long-term metabolic disease susceptibility.[1,2] Mothers benefit through accelerated postpartum recovery, reduced risks of breast and ovarian cancers, and strengthened maternal–infant bonding.[1] However, environmental stressors such as perinatal noise pollution may undermine these advantages.[3] Hospital noise levels frequently exceed WHO-recommended thresholds (45 dB), triggering maternal psychological distress and neonatal physiological instability. Noise exposure can be categorized as acute (short-term, high-intensity) or sustained (prolonged, moderate-intensity), with different physiological impacts.[4] Acute noise triggers startle reflexes and immediate stress responses, while sustained exposure leads to chronic HPA axis activation and dysregulated cortisol patterns.[4] Elevated noise levels activate the maternal hypothalamic–pituitary–adrenal (HPA) axis, increasing cortisol secretion, which may suppress oxytocin release and delay lactogenesis. Neonates exposed to chronic noise exhibit dysregulated cortisol rhythms and disrupted sleep-wake cycles, further impairing feeding behaviors.
Skin-to-skin contact (SSC), defined as placing the naked newborn on the mother’s bare chest immediately after birth, has emerged as a low-cost intervention to mitigate stress.[5] SSC can prevent neonatal hypoglycemia, stabilize neonatal cardiorespiratory parameters, and enhance maternal responsiveness through oxytocin-mediated pathways.[6,7,8] Despite the established benefits of SSC in controlled environments, significant research gaps remain regarding its efficacy under adverse environmental conditions. While SSC’s stress-reducing properties are well-documented, its potential role as a buffer against environmental noise stressors represents an unexplored area with important clinical implications.
This retrospective cohort study investigated the protective effect of noise management and SSC on noise-induced stress effects on breastfeeding self-efficacy and neonatal cortisol regulation. This study aimed to evaluate SSC’s potential benefits to reduce noise-induced stress and to increase breastfeeding self-efficacy.
MATERIALS AND METHODS
Study Subjects and Grouping
This study conducted a retrospective analysis of mother–infant pairs admitted to our hospital. A total of 204 pairs were assessed for eligibility between January 2023 and January 2025. Among them, 12 were excluded due to incomplete data, and 10 were excluded due to maternal complications. Ultimately, 182 mother–infant pairs were enrolled in the final analysis. Participants were divided into three cohorts based on intervention methods: the Noise Control group (n =55), the Standard group (n =62), and the Noise Control + SSC group (n =65). Two researchers independently cross-validated electronic medical records, environmental monitoring logs, and laboratory datasets, resolving discrepancies through consensus. Written informed consent was obtained retrospectively under ethical approval from our hospital ethics committee (2024KY-057-02), adhering to the Declaration of Helsinki principles.
Sample Size Calculation
The sample size was determined through power analysis targeting the primary outcome of neonatal salivary cortisol reduction, a key biomarker of stress response modulation.[9] Based on preliminary data from a previous study, we estimated a standardized effect size (Cohen’s d = 1.10).[7] Analysis was performed using G*Power 3.1 (Heinrich-Heine-Universität Düsseldorf, German) with one-way ANOVA, assuming α = 0.05 and power (1−β) = 0.80. The formula applied was: nij = ((Zi−j(i)T + Zi−j)2 × (σi2 + σj2))/δij2, in which n = max{nij, pairs(i,j)}, σi2 and σj2 indicate estimated variance of each group, and δij indicates effect size between groups. Our pilot data yielded the following parameters: σ1 (Standard group) = 0.16, σ2 (Noise Control group) = 0.14, σ3 (Noise Control + SSC group) = 0.13, δ12 (effect size between Standard and Noise Control groups) = 0.13, δ13 (effect size between Standard and Noise Control + SSC groups) = 0.24, and δ23 (effect size between Noise Control and Noise Control + SSC groups) = 0.11. A minimum sample size of 52 in each group was required. Our cases in each group (55, 62, 65, respectively) met the threshold to provide adequate statistical power.
Patient Selection
Inclusion criteria comprised: (1) Term infants (gestational age ≥37 weeks) delivered via uncomplicated vaginal birth; (2) Maternal age between 18 and 40 years old and willing to exclusive breastfeed; (3) 5-min Apgar scores ≥ 8; (4) Normal hearing for both mothers and infants; (5) Singleton pregnancy; (6) Complete medical records. Exclusion criteria included: (1) Maternal comorbidities or complications (such as gestational hypertension, preeclampsia, gestational diabetes, or placental abruption); (2) Neonates with severe complications including birth asphyxia, respiratory distress syndrome, or sepsis; (3) Neonates with congenital malformations or chromosomal abnormalities; (4) Maternal impaired consciousness or with psychiatric disorders.
Intervention Protocols
The Standard group received standard postpartum care in delivery rooms and the inpatient ward. Routine procedures included immediate drying with pre-warmed towels, delayed maternal contact until completion of initial assessments (Apgar scoring, weight and length measurements), and placement in radiant warmers. Breastfeeding initiation followed hospital protocols (typically within 1–2 h post-birth), with mothers receiving standardized lactation counseling at 6-h intervals. Noise sources (such as equipment alarms, staff conversations) were not actively mitigated, reflecting real-world high-noise obstetric settings. Physiological monitoring (Philips IntelliVue MX750) tracked neonatal heart rate and oxygen saturation for 72 h.
The Noise Control group received care in sound-attenuated delivery rooms and wards (Leq ≤45 dB), achieved through architectural modifications (acoustic panels, double-glazed windows) and operational protocols (restricted staff entry, silenced nonessential equipment alarms). Neonates underwent identical routine procedures as the Standard group (delayed maternal contact, radiant warmer placement) but within a noise-controlled environment. Mothers received identical lactation support schedules to control for counseling effects.
In the Noise Control + SSC group, the noise control methods were the same as the Noise Control group. SSC is defined as placing the naked newborn directly on the mother’s bare chest immediately after birth, with the infant covered with a warm blanket on the back to maintain temperature while maximizing skin-to-skin surface area contact between mother and baby. Neonates were placed on the mothers’ bare chest within 5 min postdelivery, maintaining uninterrupted SSC for ≥60 min until the first breastfeeding finished. SSC protocols included: (1) delayed routine procedures (weighing, bathing) until after contact, (2) continuous cardiorespiratory monitoring via wireless probes (Masimo Radical-7) to avoid separation, and (3) maternal coaching by SSC-trained nurses to optimize positioning and latch. Contact duration was extended throughout the 72-h hospitalization during feeding/sleeping periods. The cumulative SSC time was monitored using caregiver logs, where mothers or their family members recorded the duration of SSC during these periods.
Observational Indicators
(1) Demographic Characteristics: Maternal age, gestational age at delivery (completed weeks), and neonatal sex were extracted from electronic medical records, with cross-verification between prenatal registration data and delivery summaries. Parity (primiparous/multiparous) was defined as the number of prior live births ≥28 weeks. Maternal education level (categorized as ≤high school, college, or postgraduate) and marital status (married/unmarried) were obtained via structured self-report questionnaires.
(2) Noise Measurement: Noise measurement was conducted using Sound Analyzer (Bruel & Kjaer Sound & Vibration Measurement A/S, Denmark). For delivery room assessments, continuous monitoring occurred throughout active labor and immediate postpartum periods (first 2 h after birth), with the sound meter positioned 1 m from the maternal bed. Ward noise was evaluated in two periods: daytime measurements (08:00–20:00) and nighttime measurements (20:00–08:00) were performed on postpartum 1–3 days, capturing representative 24-h cycles. The device recorded equivalent continuous sound pressure levels (Leq) at 5-min intervals, with mean noise levels calculated from hourly averages and peak levels identified as maximum instantaneous dB(A) values during each monitoring period.
(3) Mother–Infant Interaction and Breastfeeding Competence: Maternal breastfeeding self-efficacy was assessed using the 14-item Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF; Cronbach’s α = 0.89).[10,11] The mothers were requested to finish the scale at 24 and 72 h postpartum. Items were scored on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree), with total scores ranging from 14 to 70 and higher scores indicating better confidence. Infant breastfeeding competency was evaluated by trained nurses at discharge using the Infant Breastfeeding Assessment Tool (IBFAT; Cronbach’s α = 0.78), which assesses latch quality, suckling pattern, swallowing, and maternal comfort.[12,13] Each domain scored 0–2 points, with a total range: 0–8 points, and higher scores indicating better feeding performance.
(4) Maternal and Neonatal Stress Biomarkers: Neonatal physiological stress parameters, including heart rate (HR) and oxygen saturation (SpO2), were monitored using a patient monitor (Philips Healthcare, IntelliVue MX750, Netherlands) at birth and 2 h postpartum. Maternal and neonatal salivary cortisol levels were quantified using the Enzyme Immunoassay Kit (Salimetrics LLC, USA, Catalog No. 1-3002) following standardized protocols. Maternal saliva samples were collected at 24 and 72 h postpartum, while neonatal samples were obtained at birth (within 10 min after cord clamping), 24, and 72 h.
(5) Breastfeeding Activities: The time to initiate breastfeeding was defined as the duration in minutes from birth to the onset of sustained effective suckling lasting at least 5 min, recorded by nursing staff. Exclusive breastfeeding rates at 72 h postpartum were determined through hospital lactation logs documenting all oral intake. Post-discharge exclusive breastfeeding status was assessed via structured telephone interviews at 30 days postpartum.
Statistical Analysis
Data were analyzed using IBM SPSS Statistics 28.0 (IBM Corp., USA) and visualized with GraphPad Prism 9.0 (GraphPad Software, USA). Continuous variables were assessed for normality via the Shapiro–Wilk test. Normally distributed data were reported as mean ± standard deviation (SD), and comparisons of three groups were conducted using one-way ANOVA and Tukey’s HSD for post-hoc analyses. Categorical variables were summarized as frequencies (%) and assessed using χ2 tests or Fisher’s exact tests for sparse cells (<5 expected counts). All tests were two-tailed, with P < 0.05 considered statistically significant.
RESULTS
Demographic Data
Table 1 demonstrated comparable baseline characteristics across the three groups, with no statistically significant differences in maternal age, gestational weeks, marriage status, educational levels, or parity distribution (P > 0.05). This homogeneity ensured minimal confounding bias for subsequent analyses of noise control and SSC intervention effects.
Table 1.
Demographic data of the three groups
| Item | Standard group (n =62) | Noise Control group (n = 55) | Noise Control + SSC group (n =65) | Statistic | P |
|---|---|---|---|---|---|
| Maternal age (years) | 28.52 ± 4.21 | 29.13 ± 3.82 | 27.88 ± 4.53 | F = 1.314 | 0.271 |
| Neonatal sex (n, %) | χ2 = 0.345 | 0.842 | |||
| Male | 30 (48.39%) | 26 (47.27%) | 34 (52.31%) | ||
| Female | 32 (51.61%) | 29 (52.73%) | 31 (47.69%) | ||
| Gestational weeks | 39.12 ± 1.08 | 39.34 ± 0.97 | 38.95 ± 1.15 | F = 1.964 | 0.143 |
| Marriage status (n, %) | χ2 = 0.404 | 0.817 | |||
| Married | 53 (85.48%) | 46 (83.64%) | 57 (87.69%) | ||
| Unmarried | 9 (14.52%) | 9 (16.36%) | 8 (12.31%) | ||
| Educational levels (n, %) | |||||
| ≤High school | 19 (30.65%) | 15 (27.27%) | 16 (24.62%) | χ2 = 0.669 | 0.955 |
| College | 31 (50.00%) | 30 (54.55%) | 36 (55.38%) | ||
| Postgraduate | 12 (19.35%) | 10 (18.18%) | 13 (20.00%) | ||
| Parity (n, %) | χ2 = 0.793 | 0.673 | |||
| Primiparous | 42 (67.74%) | 36 (65.45%) | 47 (72.31%) | ||
| Multiparous | 20 (32.26%) | 19 (34.55%) | 18 (27.69%) |
Note: SSC, skin-to-skin contact.
Noise Level
As shown in Table 2, the noise levels exhibited significant variations among the three groups across both delivery and ward environments. In the Standard Group, delivery rooms demonstrated substantially higher ambient and peak noise intensities compared to ward settings during both daytime and nighttime periods (P < 0.05). Noise control interventions effectively attenuated these levels, with the Noise Control and Noise Control + SSC Groups achieving comparable reductions in all measured parameters (P > 0.05).
Table 2.
Noise Levels among three groups, dB(A)
| Location | Period | Parameter | Standard Group (n =62) | Noise Control Group (n =55) | Noise Control + SSC Group (n = 65) | F | P |
|---|---|---|---|---|---|---|---|
| Delivery room | – | Mean Leq | 65.33 ± 4.82 | 52.17 ± 3.21* | 51.91 ± 3.16* | 247.8 | <0.001 |
| – | Peak Lmax | 72.75 ± 5.61 | 58.04 ± 4.84* | 57.84 ± 5.30* | 161.3 | <0.001 | |
| Ward room | Daytime | Mean Leq | 58.81 ± 3.56 | 48.56 ± 2.64* | 49.38 ± 2.58* | 224.2 | <0.001 |
| Peak Lmax | 63.03 ± 5.25 | 53.28 ± 3.32* | 54.03 ± 3.26* | 156.7 | <0.001 | ||
| Nighttime | Mean Leq | 52.71 ± 3.18 | 42.82 ± 2.31* | 43.69 ± 2.28* | 263.9 | <0.001 | |
| Peak Lmax | 57.92 ± 4.87 | 47.71 ± 3.02* | 48.50 ± 2.64* | 147.5 | <0.001 |
Note: * Compared with the Standard group, P < 0.05. SSC, skin-to-skin contact.
Mother–Infant Interaction and Breastfeeding Competence
As shown in Table 3, at 24 h postpartum, the Noise Control + SSC group exhibited the highest BSES-SF and IBFAT scores compared to the Standard group and Noise Control group (P < 0.05), and the scores of the Noise Control group was also higher than the Standard group (P < 0.05). By 72 h, the protective effects of noise control and SSC were still pronounced: the Noise Control + SSC group achieved best BSES-SF and IBFAT scores statistically comparable to the Noise Control group and Standard group (P < 0.05). This temporal progression suggested that noise control effectively reduced sustained noise-induced stress on maternal–infant pairs. In addition, SSC exhibited extra protective effects against noise-induced stress.
Table 3.
Comparison of BSES-SF and IBFAT scores
| Item | Standard group (n =62) | Noise Control group (n =55) | Noise Control + SSC group (n =65) | F | P |
|---|---|---|---|---|---|
| BSES-SF score | |||||
| 24 h postpartum | 48.35 ± 7.82 | 59.64 ± 6.15* | 64.28 ± 6.97*# | 84.95 | <0.001 |
| 72 h postpartum | 52.10 ± 8.03† | 60.15 ± 6.34*† | 65.87 ± 5.92*†# | 64.93 | <0.001 |
| IBFAT Score | |||||
| 24 h postpartum | 4.65 ± 1.28 | 5.74 ± 1.13* | 6.52 ± 0.28*# | 57.45 | <0.001 |
| 72 h postpartum | 5.82 ± 1.35† | 6.93 ± 0.65*† | 7.44 ± 0.41*†# | 53.37 | <0.001 |
Note: * Compared with the Standard group, P < 0.05; # Compared with the Noise Control group, P < 0.05. † Compared with 24 h postpartum. BSES-SF, Breastfeeding Self-Efficacy Scale-Short Form; IBFAT, Infant Breastfeeding Assessment Tool; SSC, skin-to-skin contact.
Stress Markers
Maternal and neonatal stress biomarkers are shown in Table 4. Neonates in the Standard group demonstrated persistently elevated cortisol levels compared to the Noise Control group and Noise Control + SSC group at both 24 and 72 h postpartum (P < 0.05). Noise control intervention partially attenuated cortisol levels. Noise Control + SSC group showed decreased cortisol levels at 24 and 72 h postpartum compared to the Standard group and Noise Control group (P < 0.05). Similarly, maternal cortisol in the Standard group maintained a relatively high level at 72 h, while the Noise Control + SSC group showed even lower levels than the Noise Control group (P < 0.05). Additionally, the neonates in the Standard group showed elevated neonatal HR and reduced SpO₂ during the first 2 h postpartum (P < 0.05). Noise control alone and noise control + SSC significantly mitigated acute physiological stress induced by noise, with lower HR and increased SpO₂ compared to the Standard group (P < 0.05).
Table 4.
Comparison of Stress Markers
| Item | Standard group (n =62) | Noise Control group (n =55) | Noise Control + SSC group (n =65) | F | P |
|---|---|---|---|---|---|
| Neonatal cortisol (µg/dL) | |||||
| At birth | 1.05 ± 0.21 | 1.02 ± 0.18 | 1.03 ± 0.19 | 0.693 | 0.367 |
| 24 h postpartum | 0.78 ± 0.15† | 0.65 ± 0.13*† | 0.53 ± 0.12*†# | 55.36 | <0.001 |
| 72 h postpartum | 0.55 ± 0.11† | 0.41 ± 0.09*† | 0.34 ± 0.08*# | 81.31 | <0.001 |
| Maternal cortisol (µg/dL) | |||||
| At delivery | 2.15 ± 0.38 | 2.10 ± 0.35 | 2.16 ± 0.37 | 0.643 | 0.443 |
| 24 h postpartum | 0.92 ± 0.17† | 0.75 ± 0.15*† | 0.68 ± 0.14*†# | 40.46 | <0.001 |
| 72 h postpartum | 0.76 ± 0.13† | 0.62 ± 0.11*† | 0.54 ± 0.10*†# | 60.25 | <0.001 |
| Neonatal HR (bpm) | |||||
| At birth | 122.43 ± 7.32 | 123.63 ± 7.90 | 122.62 ± 7.25 | 0.428 | 0.653 |
| 2 h postpartum | 156.28 ± 8.73 | 148.59± 7.31* | 144.16 ± 6.52*# | 41.42 | <0.001 |
| Neonatal SpO2 (%) | |||||
| At birth | 91.31 ± 1.07 | 91.75 ± 1.23 | 91.42 ± 1.13 | 2.315 | 0.102 |
| 2 h postpartum | 94.23 ± 2.12 | 96.47 ± 1.89* | 97.82 ± 1.63*# | 58.33 | <0.001 |
Note: * Compared with the Standard group, P < 0.05; # Compared with the Noise Control group, P < 0.05. †Compared with 24h postpartum. HR, heart rate; SSC, skin-to-skin contact; SpO₂, peripheral oxygen saturation.
Breastfeeding Activity
As shown in Table 5, the Standard group demonstrated delayed breastfeeding initiation compared to both Noise Control and Noise Control + SSC groups (P < 0.05). Exclusive breastfeeding rates at 72 h were lowest in the Standard group (P < 0.05), while at 30 days postpartum, the exclusive breastfeeding rates showed no difference among groups (P > 0.05).
Table 5.
Comparison of Breastfeeding Activity Indicators
| Item | Standard group (n =62) | Noise Control group (n =55) | Noise Control + SSC group (n =65) | Statistic | P |
|---|---|---|---|---|---|
| Time to first breastfeeding (min) | 92.40 ± 28.64 | 54.73 ± 16.80* | 38.52 ± 12.30*# | F=114.7 | <0.001 |
| Exclusive breastfeeding rate (n,%) | |||||
| 72 h postpartum | 36 (58.06%) | 42 (76.36%) | 54 (83.08%) | χ2 = 10.546 | 0.005 |
| 30 days postpartum | 41 (66.13 %) | 40 (72.73%) | 52 (80.00%) | χ2= 3.108 | 0.211 |
Note: * Compared with the Standard group, P < 0.05; # Compared with the Noise Control group, P < 0.05. SSC, skin-to-skin contact.
DISCUSSION
Environmental noise during childbirth can increase stress for both mothers and infants, disrupting breastfeeding confidence and the baby’s natural stress regulation.[14] Our findings highlighted both noise management and SSC as complementary practical interventions to address this gap. The following sections explore how noise control and SSC work to lessen noise effects, improve mother-baby bonding, and support breastfeeding success in clinical environments.
Mothers and newborns are inevitably exposed to hospital noise pollution. Evidence indicated that noise not only activates the hypothalamic–pituitary–adrenal (HPA) axis, triggering physiological stress responses, but also negatively impacts maternal mental health, increasing risks of anxiety and irritability.[15,16] Our findings aligned with these observations: the Standard group exhibited significantly higher maternal and neonatal salivary cortisol levels at 24 and 72 h postpartum compared to the Noise Control group. The first 2 h postpartum represent a critical period for neonatal adaptation to extrauterine life, during which autonomic nervous system regulation is highly dynamic.[17] In this study, neonates exposed to noise showed elevated HR and reduced SpO₂ at 2 h postpartum compared to the Noise Control group, further confirming noise as a stressor. Notably, cortisol levels did not differ between groups immediately at birth/delivery. This may be due to acute stressors, such as birth trauma and pain, which could have overshadowed the effects of noise. Our study demonstrated that noise control interventions significantly reduced stress biomarkers in both mothers and infants. The Noise Control group showed lower cortisol levels and improved physiological parameters compared to the Standard group, highlighting the effectiveness of maintaining ambient noise below 45 dB in perinatal settings. This finding supports implementing acoustic modifications in maternity wards as a fundamental intervention to improve maternal–infant outcomes.[18] On the other hand, SSC intervention further mitigated these adverse effects beyond noise control alone. Despite noise exposure, the Noise Control + SSC group demonstrated lower cortisol levels, stabilized HR, and higher SpO₂ compared to both other groups.
Sustained SSC promotes maternal oxytocin release, a neurohormone that inhibits excessive HPA axis activation, thereby reducing cortisol secretion.[19,20] Simultaneously, SSC can offer newborns direct physical stabilization and emotional security, dampening autonomic stress responses and fostering physiological regulation.[21,22] Beyond HPA axis modulation, SSC activates parasympathetic nervous system dominance in both mothers and infants, buffering against environmental noise stressors by preventing stress responses.[20] Additionally, SSC positively modulates infant arousal behaviors through sensory integration pathways, normalizing startle reflexes necessary for successful feeding interactions.[23] Similarly, excessive noise can disrupt neuroendocrine signaling through acoustic stressor pathways in the amygdala and hypothalamus, interfering with oxytocin release necessary for successful lactation and bonding.[24] Noise reduction likely prevents overstimulation of the auditory pathway that normally triggers sympathetic activation and subsequent cortisol release.[18] The combined approach of noise management and SSC appears to offer synergistic benefits that exceed those of either intervention alone. While noise control addresses the environmental stressor directly, SSC provides physiological and psychological buffering mechanisms that enhance resilience to any remaining environmental challenges. This dual intervention strategy represents a comprehensive approach to optimizing the perinatal environment. However, prolonged SSC faces challenges such as maternal fatigue, post-cesarean mobility limitations, and monitoring constraints. Safety concerns, including rare infant falls, require proper parental education and observation. For the standard care group with elevated stress, alternatives like music therapy or acoustic modifications could be considered when noise control is not feasible.
Breastfeeding can establish immune and microbiome benefits for neonates while aiding maternal recovery.[1] However, breastfeeding self-efficacy is highly sensitive to environmental stressors.[25] Noise-induced anxiety and disrupted mother-infant interactions can impair breastfeeding confidence and delay lactation initiation.[26] Our results revealed that the Standard group had consistently lower BSES-SF and IBFAT scores, as well as prolonged time to first breastfeeding compared to the Noise Control group. These findings underscore noise’s effects on maternal-infant bonding and feeding behaviors. SSC counteracted these disruptions even under noise exposure. The Noise Control + SSC group achieved better BSES-SF and IBFAT, comparable to the Noise Control group, with significantly shorter breastfeeding initiation times. Enhanced maternal-infant synchrony during SSC likely explains this improvement, as tactile interaction fosters emotional bonding and reduces separation-related stress.[7,27] Furthermore, the Noise Control + SSC group maintained higher exclusive breastfeeding rates at 72 h postpartum than the Standard group, highlighting SSC’s short-term benefits.[28] These results aligned with studies linking SSC to improved maternal responsiveness and neonatal behavioral organization through oxytocin-mediated pathways.[20] However, although the interventions significantly improved exclusive breastfeeding rates at 72 h postpartum, these differences were not sustained at 30 days. This may be due to the influence of other factors, such as social support, maternal health, and lifestyle changes, which could have overshadowed the initial benefits of noise control and SSC.
This study has several limitations. The single-center retrospective design and modest sample size may limit the generalizability of findings across diverse populations or healthcare systems. While major confounders such as parity and maternal education were controlled, unmeasured factors like maternal anxiety subtypes or infant temperament could influence SSC’s effectiveness. Additionally, the lack of an SSC + Noise Control group makes it difficult to distinguish SSC’s intrinsic benefits from its role in mitigating noise-specific stress, leaving open whether observed improvements stem from bonding mechanisms or stress buffering alone. Furthermore, although SSC duration was standardized, variability in real-time noise exposure and maternal adherence to SSC protocols were not rigorously monitored. Procedural variations between groups, such as delayed weighing in the Noise Control + SSC protocol, represent methodological confounding variables that may have independently influenced the measured outcomes. Future research should adopt multicenter prospective designs with four experimental arms (Noise, Noise + SSC, Noise Control, and SSC + Noise Control) to clarify SSC’s context-dependent mechanisms. Incorporating wearable sensors for continuous noise and SSC tracking, combined with detailed maternal psychological evaluations, could optimize intervention personalization and efficacy.
CONCLUSION
This study demonstrated that the combination of noise management and SSC effectively mitigated perinatal stress by reducing cortisol levels and stabilizing neonatal cardiorespiratory parameters. Both interventions independently improved breastfeeding parameters, with their combined application showing enhanced effects on breastfeeding initiation and short-term exclusive breastfeeding rates. These findings support implementing both noise control and SSC as complementary, low-cost interventions in routine postpartum care protocols to optimize the perinatal environment.
Contribution statement
Jingbo Li: Led the research design and execution, managed data collection and analysis, and authored the initial draft of the manuscript. Chunxiu Zhou: Contributed to the research design, supported data analysis, and made initial revisions to the manuscript. ShangMei Dong: Provided technical guidance and ensured quality control throughout the data collection process. Xuan Chen (corresponding author): Oversaw the overall research design and supervision, offered technical and theoretical expertise, and conducted the final review and approval of the manuscript.
Availability of Data and Materials
The datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request.
Ethical Approval and Consent to Participate
This study was approved by the Nanjing Medical University Affiliated Obstetrics and Gynecology Hospital (2024KY-057-02).
Conflict of interest
The authors declare no conflicts of interest.
Acknowledgments
We thank the patients and their families for participating in this research.
Funding Statement
This study is funded by the Nanjing Medical Science and Technology Development Project (YKK24141).
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request.