Study protocol: An investigation of mother-infant signalling during breastfeeding using a randomised trial to test the effectiveness of breastfeeding relaxation therapy on maternal psychological state, breast milk production and infant behaviour and growth

Relaxation Therapy and Human Milk Feeding Outcomes: A Systematic Review and Meta-Analysis

Importance

Human milk feeding is a key public health goal to optimize infant and maternal/parental health, but global lactation outcomes do not meet recommended duration and exclusivity. There are connections between lactation and mental health.

Objective

To appraise all available evidence on whether the provision of relaxation interventions to lactating individuals improves lactation and well-being.

Data Sources

Embase, MEDLINE, CINAHL, Allied and Complementary Medicine Database, Web of Science, and the Cochrane Library were searched on September 30, 2023, and topic experts were consulted.

Study Selection

Two independent reviewers screened for eligibility. Inclusion criteria were full-text, peer-reviewed publications with a randomized clinical trial design. Techniques that were entirely physical (eg, massage) were excluded. A total of 7% of initially identified studies met selection criteria.

Data Extraction and Synthesis

Two independent reviewers extracted data and assessed risk of bias with the Cochrane Risk of Bias 2 tool. Fixed-effects meta-analysis and Grading of Recommendations, Assessment, Development, and Evaluations guidelines were used to synthesize and present evidence.

Main Outcomes and Measures

Prespecified primary outcomes were human milk quantity, length and exclusivity of human milk feeding, milk macronutrients/cortisol, and infant growth and behavior.

Results

A total of 16 studies were included with 1871 participants (pooled mean [SD] age for 1656 participants, 29.6 [6.1] years). Interventions were music, guided relaxation, mindfulness, and breathing exercises/muscle relaxation. Provision of relaxation was not associated with a change in human milk protein (mean difference [MD], 0 g/100 mL; 95% CI, 0; 205 participants). Provision of relaxation was associated with an increase in human milk quantity (standardized mean difference [SMD], 0.73; 95% CI, 0.57-0.89; 464 participants), increased infant weight gain in breastfeeding infants (MD, z score change = 0.51; 95% CI, 0.30-0.72; 226 participants), and a slight reduction in stress and anxiety (SMD stress score, -0.49; 95% CI, -0.70 to -0.27; 355 participants; SMD anxiety score, -0.45; 95% CI, -0.67 to -0.22; 410 participants).

Conclusions and Relevance

Results of this systematic review and meta-analysis suggest that provision of relaxation was associated with an increase in human milk quantity and infant weight gain and a slight reduction in stress and anxiety. Relaxation interventions can be offered to lactating parents who would like to increase well-being and improve milk supply or, where directly breastfeeding, increase infant weight gain.

Predictors of milk cortisol in North American women

OBJECTIVES

Human milk content varies across mother-child dyads, environments, and populations. Among the hormones in milk is cortisol, a glucocorticoid; its impact on the breastfeeding child is unknown. Milk cortisol may constitute a signal to the child's developing physiology which can shape characteristics (e.g., growth, temperament) to prevailing environmental conditions. This exploratory study evaluated the maternal, breastfeeding, and infant characteristics associated with milk cortisol.

METHODS

We evaluated archived milk specimens for cortisol using enzyme immunoassay and employed an information-theoretic approach to assess associations between milk cortisol and participant characteristics with linear regression modeling. Because we employed secondary data, information for some variables likely to impact milk cortisol variation (e.g., time of day, socioeconomic status, maternal or infant body mass index, milk energy density) was unavailable.

RESULTS

Participants were 48 lactating mothers from upstate New York, aged 21-40 years. Milk cortisol ranged from 0.098 to 1.007 μg/dL. Child age ranged from 1 to 26 months. In linear regression employing best fit modeling criteria, milk cortisol increased with child age (B: 0.069; p: .000; a 7.1% increase in milk cortisol for each month of child age), while child symptoms of illness (B: -0.398; p: .057; a 33% decrease) and consumption of complementary foods (B: -.525; p: .020; a 41% decrease) were associated with lower milk cortisol.

CONCLUSIONS

We speculate that increasing milk cortisol with child age plays a role in signaling development (e.g., as increasing independence increases risk for injury and other negative health outcomes), independent of the maternal stressors we could capture.

Effects of relaxation therapy on maternal psychological status and infant growth following late preterm and early-term delivery: a randomized controlled trial

BACKGROUND

Maternal stress is one modifiable variable that could influence mother-infant signaling and negatively affect breastfeeding and infant growth.

OBJECTIVES

This study aimed to test the hypothesis that relaxation therapy would reduce maternal stress and improve infant growth, behavior, and breastfeeding outcomes after late preterm (LP) and early-term (ET) delivery.

METHODS

A single-blind randomized controlled trial was conducted in healthy Chinese primiparous mother-infant pairs after LP or ET delivery (34⁺⁰-37⁺⁶ gestation weeks). Mothers were randomly assigned to the intervention group (IG, listening to relaxation meditation at least once a day) or control group (CG, normal care). Primary outcomes-changes in maternal stress (perceived stress scale), anxiety (Beck Anxiety Inventory), and infant weight and length standard deviation score-were assessed at 1 wk and 8 wks postpartum. Secondary outcomes-breast milk energy and macronutrient composition, maternal breastfeeding attitudes, infant behaviors (3-d diary), and 24-hour milk intake-were assessed at 8 wks.

RESULTS

In total, 96 mother-infant pairs were recruited. There was a significantly greater reduction in maternal perceived stress (Perceived Stress Scale score) (mean difference [MD] = 2.65; 95% CI: 0.8, 4.5) and significantly greater infant weight standard deviation score gain (MD = 0.51; 95% CI: 0.2, 0.9) from 1 wk to 8 wks in the IG than those in the CG. Exploratory analyses showed a significant interaction between intervention and sex, with greater effects on weight gain in female infants. Mothers of female infants used the intervention more frequently with significantly higher milk energy observed at 8 wks.

CONCLUSIONS

The relaxation meditation tape is a simple, effective practical tool that could easily be used in clinical settings to support breastfeeding mothers after LP and ET delivery. The findings need confirmation in larger groups and in other populations.

Support for healthy breastfeeding mothers with healthy term babies

BACKGROUND

There is extensive evidence of important health risks for infants and mothers related to not breastfeeding. In 2003, the World Health Organization recommended that infants be breastfed exclusively until six months of age, with breastfeeding continuing as an important part of the infant's diet until at least two years of age. However, current breastfeeding rates in many countries do not reflect this recommendation.

OBJECTIVES

1. To describe types of breastfeeding support for healthy breastfeeding mothers with healthy term babies. 2. To examine the effectiveness of different types of breastfeeding support interventions in terms of whether they offered only breastfeeding support or breastfeeding support in combination with a wider maternal and child health intervention ('breastfeeding plus' support).  3. To examine the effectiveness of the following intervention characteristics on breastfeeding support:      a. type of support (e.g. face-to-face, telephone, digital technologies, group or individual support, proactive or reactive);      b. intensity of support (i.e. number of postnatal contacts);      c. person delivering the intervention (e.g. healthcare professional, lay person);     d. to examine whether the impact of support varied between high- and low-and middle-income countries.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (which includes results of searches of CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform (ICTRP)) (11 May 2021) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing extra support for healthy breastfeeding mothers of healthy term babies with usual maternity care. Support could be provided face-to-face, over the phone or via digital technologies. All studies had to meet the trustworthiness criteria.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane Pregnancy and Childbirth methods. Two review authors independently selected trials, extracted data, and assessed risk of bias and study trustworthiness.  The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

This updated review includes 116 trials of which 103 contribute data to the analyses. In total more than 98,816 mother-infant pairs were included.  Moderate-certainty evidence indicated that 'breastfeeding only' support probably reduced the number of women stopping breastfeeding for all primary outcomes: stopping any breastfeeding at six months (Risk Ratio (RR) 0.93, 95% Confidence Interval (CI) 0.89 to 0.97); stopping exclusive breastfeeding at six months (RR 0.90, 95% CI 0.88 to 0.93); stopping any breastfeeding at 4-6 weeks (RR 0.88, 95% CI 0.79 to 0.97); and stopping exclusive breastfeeding at 4-6 (RR 0.83 95% CI 0.76 to 0.90). Similar findings were reported for the secondary breastfeeding outcomes except for any breastfeeding at two months and 12 months when the evidence was uncertain if 'breastfeeding only' support helped reduce the number of women stopping breastfeeding.  The evidence for 'breastfeeding plus' was less consistent. For primary outcomes there was some evidence that 'breastfeeding plus' support probably reduced the number of women stopping any breastfeeding (RR 0.94, 95% CI 0.91 to 0.97, moderate-certainty evidence) or exclusive breastfeeding at six months (RR 0.79, 95% CI 0.70 to 0.90).  'Breastfeeding plus' interventions may have a beneficial effect on reducing the number of women stopping exclusive breastfeeding at 4-6 weeks, but the evidence is very uncertain (RR 0.73, 95% CI 0.57 to 0.95). The evidence suggests that 'breastfeeding plus' support probably results in little to no difference in the number of women stopping any breastfeeding at 4-6 weeks (RR 0.94, 95% CI 0.82 to 1.08, moderate-certainty evidence). For the secondary outcomes, it was uncertain if 'breastfeeding plus' support helped reduce the number of women stopping any or exclusive breastfeeding at any time points.  There were no consistent findings emerging from the narrative synthesis of the non-breastfeeding outcomes (maternal satisfaction with care, maternal satisfaction with feeding method, infant morbidity, and maternal mental health), except for a possible reduction of diarrhoea in intervention infants.  We considered the overall risk of bias of trials included in the review was mixed. Blinding of participants and personnel is not feasible in such interventions and as studies utilised self-report breastfeeding data, there is also a risk of bias in outcome assessment.   We conducted meta-regression to explore substantial heterogeneity for the primary outcomes using the following categories: person providing care; mode of delivery; intensity of support; and income status of country.  It is possible that moderate levels (defined as 4-8 visits) of 'breastfeeding only' support may be associated with a more beneficial effect on exclusive breastfeeding at 4-6 weeks and six months. 'Breastfeeding only' support may also be more effective in reducing women in low- and middle-income countries (LMICs) stopping exclusive breastfeeding at six months compared to women in high-income countries (HICs). However, no other differential effects were found and thus heterogeneity remains largely unexplained. The meta-regression suggested that there were no differential effects regarding person providing support or mode of delivery, however, power was limited.  AUTHORS' CONCLUSIONS: When 'breastfeeding only' support is offered to women, the duration and in particular, the exclusivity of breastfeeding is likely to be increased. Support may also be more effective in reducing the number of women stopping breastfeeding at three to four months compared to later time points.  For 'breastfeeding plus' interventions the evidence is less certain. Support may be offered either by professional or lay/peer supporters, or a combination of both. Support can also be offered face-to-face, via telephone or digital technologies, or a combination and may be more effective when delivered on a schedule of four to eight visits. Further work is needed to identify components of the effective interventions and to deliver interventions on a larger scale.

MYBIOTA: A birth cohort on maternal and infant microbiota and its impact on infant health in Malaysia

Background

The microbiota plays a key role in early immunity maturation that affects infant health and is associated with the development of non-communicable diseases and allergies in later life.

Objective

The MYBIOTA is a prospective mother-infant cohort study in Malaysia aiming to determine the association between gut microbiota with infant health (temperament, gastrointestinal disorders, eczema, asthma, and developmental delays) in Selangor, Malaysia.

Methods

Pregnant mothers will be enrolled in their first trimester of pregnancy, and follow-ups will be done for infants during their first year of life. Maternal-infant biological samples (blood, feces, saliva, urine, and breast milk), anthropometric, dietary, and clinical information will be collected at different time points from early pregnancy to 12 months postpartum.

Discussion

This study could provide a better understanding of the colonization and development of the gut microbiome during early life and its impact on infant health.

Clinical trial registration

https://clinicaltrials.gov/, identifier NCT04919265.

The Associations of Breastfeeding and Postnatal Experiences With Postpartum Depression Among Mothers of Hospitalized Infants in Tertiary Hospitals

Background

Postpartum depression has been linked to undesirable outcomes for mother-infant dyads, interfering with childcare and breastfeeding practices. This study aimed to determine the prevalence of depressive symptoms among mothers during the postpartum period and its association with breastfeeding and postpartum experiences.

Methodology

This cross-sectional study involved mothers of hospitalized infants (n = 219) at two tertiary hospitals in Klang Valley, Malaysia. Mothers were screened for postpartum depression using the Edinburgh Postnatal Depression Scale with a cut-off of ≥12 for positive screening for depression. Mothers were asked to complete questionnaires on breastfeeding experience, which included breastfeeding self-efficacy and challenges. The questionnaires also collected information on postnatal experiences, including birth outcomes, anxiety and stress levels, and social support. Multiple linear regression was used to ascertain the association of postpartum depression levels with breastfeeding and postnatal experiences.

Results

Overall, 30% of mothers in this study screened positive for depression. Based on multiple linear regression, a higher score of postpartum depression was significantly associated with unpleasant breastfeeding and postnatal experiences reflected by increased scores of anxiety and stress, lower infant birth weight, increased breastfeeding problems, and lower level of social support (p < 0.005).

Conclusions

Maternal emotions, birth outcomes, breastfeeding issues, and social support were associated with postpartum depression. Efforts should be made to increase maternal support, and screening for maternal depression during infant hospital stays should be encouraged.

Differences in maternal characteristics and their associations with breastfeeding attitudes among primiparous mothers

BACKGROUND

The benefits of breastfeeding are well documented, yet substantially below half of all mothers globally meet the recommendation to exclusively breast-feed for 6 months.

OBJECTIVE

This study aimed to examine whether there were differences in maternal factors, including maternal characteristics and breastfeeding attitudes, between those who were eligible versus non-eligible to be included in a randomised trial, as exclusive breastfeeding was the eligibility criteria for the trial. It also aimed to investigate associations between maternal factors and breastfeeding attitudes.

METHOD

Primiparous pregnant mothers (n=88) completed questionnaires on demographic factors including maternity care and breastfeeding attitude using self-administered questionnaire and Iowa Infant Feeding Attitude Scale (IIFAS). Two weeks post-birth, mothers were screened for eligibility to be included in a randomised trial including assessing for exclusive breastfeeding (EBF). Findings were compared between inclusion (all EBF mothers) and exclusion groups (non-EBF).

RESULTS

Inclusion group mothers were significantly younger than those in the exclusion group (26.7±2.8 v 28.5±2.5, p=0.007) and the majority had their husband as the primary maternity care person after birth (X²=12.8, p=0.01). Inclusion group mothers had a more positive perception toward breastfeeding in public and at work on the IIFAS scale (p<0.05). The overall IIFAS score was positively associated with higher breastfeeding confidence (r=0.285, p=0.008), education levels (r=0.31, p=0.003), household income (r=0.32, p=0.003), and age (r=0.28, p=0.008).

CONCLUSION

EBF mothers (inclusion group) tend to be younger, had husband as primary care, and have more positive perception towards breastfeeding outside home. Overall, maternal characteristics and paternal support could influence breastfeeding practices and should be targeted for future intervention. Maternal attitude and perceptions about breastfeeding in public could be improved to encourage exclusive breastfeeding.

'Optimising' breastfeeding: what can we learn from evolutionary, comparative and anthropological aspects of lactation?

BACKGROUND

Promoting breastfeeding is an important public health intervention, with benefits for infants and mothers. Even modest increases in prevalence and duration may yield considerable economic savings. However, despite many initiatives, compliance with recommendations is poor in most settings - particularly for exclusive breastfeeding. Mothers commonly consult health professionals for infant feeding and behavioural problems.

MAIN BODY

We argue that broader consideration of lactation, incorporating evolutionary, comparative and anthropological aspects, could provide new insights into breastfeeding practices and problems, enhance research and ultimately help to develop novel approaches to improve initiation and maintenance. Our current focus on breastfeeding as a strategy to improve health outcomes must engage with the evolution of lactation as a flexible trait under selective pressure to maximise reproductive fitness. Poor understanding of the dynamic nature of breastfeeding may partly explain why some women are unwilling or unable to follow recommendations.

CONCLUSIONS

We identify three key implications for health professionals, researchers and policymakers. Firstly, breastfeeding is an adaptive process during which, as in other mammals, variability allows adaptation to ecological circumstances and reflects mothers' phenotypic variability. Since these factors vary within and between humans, the likelihood that a 'one size fits all' approach will be appropriate for all mother-infant dyads is counterintuitive; flexibility is expected. From an anthropological perspective, lactation is a period of tension between mother and offspring due to genetic 'conflicts of interest'. This may underlie common breastfeeding 'problems' including perceived milk insufficiency and problematic infant crying. Understanding this - and adopting a more flexible, individualised approach - may allow a more creative approach to solving these problems. Incorporating evolutionary concepts may enhance research investigating mother-infant signalling during breastfeeding; where possible, studies should be experimental to allow identification of causal effects and mechanisms. Finally, the importance of learned behaviour, social and cultural aspects of primate (especially human) lactation may partly explain why, in cultures where breastfeeding has lost cultural primacy, promotion starting in pregnancy may be ineffective. In such settings, educating children and young adults may be important to raise awareness and provide learning opportunities that may be essential in our species, as in other primates.

Maternal and Neonatal Hair Cortisol Levels and Psychological Stress Are Associated With Onset of Secretory Activation of Human Milk Production

BACKGROUND

Several factors can influence the production of mothers' own milk.

PURPOSE

To assess the influence of maternal psychological stress, maternal cortisol levels, and neonatal hair cortisol levels on timing of secretory activation.

METHODS

A prospective study was conducted at 2 public health centers in Andalusia, Spain. Participants were 60 pregnant women and their 60 neonates. Hair cortisol levels and psychological stress (pregnancy-specific stress [Prenatal Distress Questionnaire, PDQ] and perceived stress [Perceived Stress Scale, PSS]) were evaluated during the third trimester and the postpartum period. This study was part of the GESTASTRESS cohort study on the effects of stress during pregnancy.

RESULTS

Higher PDQ and PSS scores (P < .05) in the third trimester were associated with later onset of secretory activation. Higher postpartum maternal hair cortisol levels were associated with a delayed secretory activation of mother's own milk (P < .05).

IMPLICATIONS FOR RESEARCH

Future studies should look at the influence of psychological stress and cortisol levels on hormones involved in mother's own milk production.

IMPLICATIONS FOR PRACTICE

Neonatal nurses and other healthcare providers should be familiar with levels of neonates' exposure to maternal prenatal stress prior to birth.

Developmental responses to early-life adversity: Evolutionary and mechanistic perspectives

Adverse ecological and social conditions during early life are known to influence development, with rippling effects that may explain variation in adult health and fitness. The adaptive function of such developmental plasticity, however, remains relatively untested in long-lived animals, resulting in much debate over which evolutionary models are most applicable. Furthermore, despite the promise of clinical interventions that might alleviate the health consequences of early-life adversity, research on the proximate mechanisms governing phenotypic responses to adversity have been largely limited to studies on glucocorticoids. Here, we synthesize the current state of research on developmental plasticity, discussing both ultimate and proximate mechanisms. First, we evaluate the utility of adaptive models proposed to explain developmental responses to early-life adversity, particularly for long-lived mammals such as humans. In doing so, we highlight how parent-offspring conflict complicates our understanding of whether mothers or offspring benefit from these responses. Second, we discuss the role of glucocorticoids and a second physiological system-the gut microbiome-that has emerged as an additional, clinically relevant mechanism by which early-life adversity can influence development. Finally, we suggest ways in which nonhuman primates can serve as models to study the effects of early-life adversity, both from evolutionary and clinical perspectives.

[Sleep disorders as one of the indicators of postpartum depression]

Postpartum depression in ICD-10 refers to mild mental and behavioral disorders associated with physiological disorders of the postpartum period F53.0. Diagnosis is based on criteria, one of which is sleep disorders. The objective of the review is to characterize the postpartum sleep disorders and to reflect their predictor value in the development of postpartum depression. Presomnic, intrasomnic and postsomnic disorders with negative consequences for both the mother and her child were found in sleep disorders of women with postpartum depression. Depression with sleep disorders significantly affect the quality of life of the mother and infant. Sleep disorders are one of the predictors of postpartum depression. Improving of sleep quality is an effective way to prevent the effects of postpartum depression.

Randomized controlled trial investigating the effects of a breastfeeding relaxation intervention on maternal psychological state, breast milk outcomes, and infant behavior and growth

BACKGROUND

Biological signaling and communication between mothers and infants during breastfeeding may shape infant behavior and feeding. This signaling is complex and little explored in humans, although it is potentially relevant for initiatives to improve breastfeeding rates.

OBJECTIVES

The aim of this study was to investigate physiological and psychological aspects of mother-infant signaling during breastfeeding experimentally, testing the effects of a relaxation intervention on maternal psychological state, breast milk intake, milk cortisol levels, and infant behavior and growth.

METHODS

Primiparous breastfeeding mothers and full-term infants were randomly assigned to receive relaxation therapy [intervention relaxation group; n = 33 (RG)] or to the control group [n = 31 (CG); no relaxation therapy] at 2 wk postpartum. Both groups received standard breastfeeding support. Home visits were conducted at 2 (HV1), 6 (HV2), 12 (HV3) and 14 (HV4) wk to measure maternal stress and anxiety, breast milk intake and milk cortisol, and infant behavior and growth.

RESULTS

RG mothers had lower stress scores postintervention than the CG (HV3 ∆ = -3.13; 95% CI: -5.9, -0.3) and lower hindmilk cortisol at HV1 (∆ = -44.5%; 95% CI: -76.1%, -12.9%) but not at HV2. RG infants had longer sleep duration (∆ = 82 min/d; 95% CI: 16, 149 min/d) at HV2 and higher gains in weight and body mass index standardized deviation score than the CG infants (∆ = 0.76; 95% CI: 0.3, 1.22; and ∆ = 0.59; 95% CI: 0.09, 1.1, respectively). RG infants had a mean milk intake at HV3 that was 227 g/d higher than that of the CG infants (P = 0.031) after controlling for gender and milk intake at HV1.

CONCLUSIONS

The trial shows the effectiveness of a simple relaxation intervention for improving maternal and infant outcomes and identifies some potential signaling mechanisms for investigation in future and larger studies, especially in settings where mothers are more stressed, such as those with preterm or low birth weight infants. This trial was registered at clinicaltrials.gov as NCT01971216.

The effectiveness of interventions using relaxation therapy to improve breastfeeding outcomes: A systematic review

Maternal psychological state is recognised to influence lactation success, largely by affecting milk ejection. Thus, increased psychological distress can disrupt milk flow and in the long‐term, affect milk synthesis. Conversely, it is possible that milk ejection could be improved by using relaxation therapy during breastfeeding. We performed a systematic review to evaluate the effectiveness of interventions using relaxation therapy to improve breastfeeding outcomes and to assess the consequent impact(s) on infant growth and behaviour. A literature search was performed using the PRISMA guidelines where we included intervention studies (including nonrandomised controlled studies) using relaxation therapy in breastfeeding mothers during the post‐natal period. Out of 147 identified records at the initial search, 5 studies were eligible, of which 3 were randomised controlled trials and 2 were nonrandomised or quasi‐experimental studies. These studies were conducted in Europe, America, and India and included 311 mother–infant pairs, of which 64 infants were full‐term and 247 were premature infants. Relaxation therapy was shown to increase milk yield in mothers of preterm infants in 2 randomised trials, however, the milk sampling protocol for these studies could be questioned. None of the studies investigated the consequent effects on infant outcomes. Overall, limited evidence was found on the effectiveness of relaxation therapy on breast milk composition and infant outcomes. Experimental studies with better standardisation of protocol and robust methodological design are needed to investigate the effectiveness of relaxation therapy on both breastfeeding and infant growth and behavioural outcomes.