The evidence for public health recommendations on infant feeding

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.

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

Background

The physiological and psychological signalling between mother and infant during lactation is one of the prominent mother-infant factors that may influence breastfeeding outcomes. The infant can ‘signal’ his needs through vocalisation, and the mother can respond by allowing or restricting nipple access, which might alter the breast milk composition or volume. This may lead to parent-offspring conflict during the lactation period. Challenging infant behaviour has also been associated with maternal psychological distress, which might affect breastfeeding performance. Most attempts to improve breastfeeding rates focus on providing additional support, yet many aspects of the breastfeeding process are poorly understood. Thus, our objective is to investigate mother-infant signalling during breastfeeding by manipulating maternal psychological state using a relaxation therapy intervention. The study will test the hypothesis that mothers who listen to the therapy will be more relaxed/less stressed and this will favourably alter breast milk composition and/or affect milk volume and hence influence infant outcomes.

Methods

A randomised controlled trial will be conducted in first-time breastfeeding mothers and their new-born infants. Pregnant mothers will be recruited at antenatal clinics in Selangor, Malaysia, and four home visits will be carried out at 2, 6, 12 and 14 weeks postnatally. Participants will be randomised into a control and an intervention group in the early post-partum period. Mothers from the intervention group will be asked to listen daily to an audio recording with relaxation therapy during breastfeeding. Maternal psychological state, breastfeeding practices and infant behaviour will be assessed using validated questionnaires. Milk volume will be measured using stable isotopes. Breast milk samples will be collected to measure macronutrient content and hormone levels. Anthropometric measurements (weight, length and head circumference) will be performed during all home visits, including body composition at week 14.

Discussion

The main outcomes will be the effect of the intervention on maternal psychological state, milk production, cortisol levels, and infant behaviour and growth. Secondary outcomes will be associations between breast milk composition and infant appetite and growth. This study aims to provide a greater understanding of maternal-infant factors which influence breastfeeding outcomes and which may be useful targets for future interventions.

Trial registration

ClinicalTrials.gov identifier: NCT01971216.

The role of infant nutrition in the global epidemic of non-communicable disease

Non-communicable diseases (NCD) and atherosclerotic CVD in particular, are the most important health problems of the 21st century. Already in every world region except Africa, NCD account for greater mortality than communicable, maternal, perinatal and nutritional conditions combined. Although modifiable lifestyle factors in adults are the main determinants, substantial evidence now suggests that factors in early life also have a major role in the development of NCD; commonly referred to as the Developmental Origins of Health and Disease hypothesis. Factors in utero, early postnatal life and throughout childhood, have been shown to affect NCD by influencing risk factors for CVD such as obesity, diabetes, hypertension and dyslipidaemia. Infant nutrition (e.g. breastfeeding rather than bottle feeding) and a slower pattern of infant weight gain have been shown to be particularly protective against later risk of obesity and CVD in both low- and high-income countries. The mechanisms involved are poorly understood, but include epigenetic changes; effects on endocrine systems regulating body weight, food intake and fat deposition; and changes in appetite regulation. As a consequence, strategies to optimise early life nutrition could make a major contribution to stemming the current global epidemic of NCD. This review will consider the role of early life factors in the development of NCD, focusing on the impact of infant nutrition/growth on obesity and CVD. The review will highlight the experimental (randomised) evidence where available, briefly summarise the underlying mechanisms involved and consider the implications for public health.

Association between tactile over-responsivity and vegetable consumption early in the introduction of solid foods and its variation with age

The main aim of the current study was to test the hypothesis that early reactions to a vegetable in infants may be associated with sensory processing, in particular, tactile over-responsivity. A secondary aim was to see whether the relationship between sensory over-responsivity and vegetable consumption would be moderated by the age of the infant. A sample of 61 infants was recruited from children's centres and playgroups in South Birmingham, UK. Infant's acceptance of carrot was measured in grams during the first week of complementary feeding in one testing situation. Mothers filled in self-report measures of infant sensory processing, as well as their own fruit and vegetable consumption. Infant carrot consumption in the first week of solid food consumption was negatively associated with total sensory over-responsivity across different sensory domains (P < 0.01). Across the sensory domains only tactile over-responsivity predicted carrot consumption, accounting for 10.7% of the variance in consumption scores. Across the sample as a whole, the relationship between carrot consumption and tactile over-responsivity varied according to the age of introduction to solid foods. In particular, those who were weaned later and had high tactile over-responsivity ate less carrot (P < 0.001). Infants who were weaned early ate a similar amount of carrot, regardless of their tactile responsivity (P > 0.05). This study constitutes some of the first evidence to suggest that sensory processing styles be associated with early vegetable acceptance; however, more research is needed to evaluate the best strategies to use when feeding infants who are sensitive to tactile information.

Bed-sharing by breastfeeding mothers: who bed-shares and what is the relationship with breastfeeding duration?

AIM

To explore the link between breastfeeding duration and bed-sharing frequency among women reporting a prenatal intention to breastfeed.

METHODS

About 870 participants in a randomised breastfeeding trial, recruited at mid-pregnancy, provided weekly snapshots of breastfeeding and bed-sharing behaviour for 26 weeks following birth. Strength of prenatal breastfeeding intent was recorded at recruitment using Likert-type scales.

RESULTS

Outcomes were frequency of bed-sharing at home for at least one hour per week, and time to cessation of breastfeeding. There were insufficient data to classify bed-sharing pattern in 192/870 (22%) of mothers. Of the remainder, 44% (299/678) of participants 'rarely' or 'never' bed-shared, 28% (192/678) did so 'intermittently' and 28% (187/678) did so 'often'. These three groups did not differ significantly in marital status, income, infant gestational age, maternal age or delivery mode. Significantly, more participants who bed-shared 'often' reported strong prenatal breastfeeding intent (70% vs. 57% and 56% for 'intermittent' and 'rare' bed-share groups) and attached high prenatal importance to breastfeeding (95% vs. 87% and 82%). Significantly, more women who bed-shared frequently were breastfeeding at 6 months (p < 0.0001) than those who intermittently or rarely/never bed-shared.

CONCLUSION

Women with strong motivation to breastfeed frequently bed-share. Given the complex relationship between bed-sharing and sudden infant death syndrome (SIDS) appropriate guidance balancing risk minimisation with support for breastfeeding mothers is crucial.

Nutrition in early life and the programming of adult disease: a review

Foetal development and infancy are life stages that are characterised by rapid growth, development and maturation of organs and systems. Variation in the quality or quantity of nutrients consumed by mothers during pregnancy, or infants during the first year of life, can exert permanent and powerful effects upon developing tissues. These effects are termed 'programming' and represent an important risk factor for noncommunicable diseases of adulthood, including the metabolic syndrome and coronary heart disease. This narrative review provides an overview of the evidence-base showing that indicators of nutritional deficit in pregnancy are associated with a greater risk of type-2 diabetes and cardiovascular mortality. There is also a limited evidence-base that suggests some relationship between breastfeeding and the timing and type of foods used in weaning, and disease in later life. Many of the associations reported between indicators of early growth and adult disease appear to interact with specific genotypes. This supports the idea that programming is one of several cumulative influences upon health and disease acting across the lifespan. Experimental studies have provided important clues to the mechanisms that link nutritional challenges in early life to disease in adulthood. It is suggested that nutritional programming is a product of the altered expression of genes that regulate the cell cycle, resulting in effective remodelling of tissue structure and functionality. The observation that traits programmed by nutritional exposures in foetal life can be transmitted to further generations adds weight the argument that heritable epigenetic modifications play a critical role in nutritional programming.