Trade-offs underlying maternal breastfeeding decisions: a conceptual model

An equitable, community-engaged translational framework for science in human lactation and infant feeding-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 5

Human milk is the ideal source of nutrition for most infants, but significant gaps remain in our understanding of human milk biology. As part of addressing these gaps, the Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN) Project Working Groups 1-4 interrogated the state of knowledge regarding the infant-human milk-lactating parent triad. However, to optimize the impact of newly generated knowledge across all stages of human milk research, the need remained for a translational research framework specific to the field. Thus, with inspiration from the simplified environmental sciences framework of Kaufman and Curl, Working Group 5 of the BEGIN Project developed a translational framework for science in human lactation and infant feeding, which includes 5 nonlinear, interconnected translational stages, T1: Discovery; T2: Human health implications; T3: Clinical and public health implications; T4: Implementation; and T5: Impact. The framework is accompanied by 6 overarching principles: 1) Research spans the translational continuum in a nonlinear, nonhierarchical manner; 2) Projects engage interdisciplinary teams in continuous collaboration and cross talk; 3) Priorities and study designs incorporate a diverse range of contextual factors; 4) Research teams include community stakeholders from the outset through purposeful, ethical, and equitable engagement; 5) Research designs and conceptual models incorporate respectful care for the birthing parent and address implications for the lactating parent; 6) Research implications for real-world settings account for contextual factors surrounding the feeding of human milk, including exclusivity and mode of feeding. To demonstrate application of the presented translational research framework and its overarching principles, 6 case studies are included, each illustrating research gaps across all stages of the framework. Applying a translational framework approach to addressing gaps in the science of human milk feeding is an important step toward the aligned goals of optimizing infant feeding across diverse contexts as well as optimizing health for all.

Evolutionary biological perspectives on current social issues of breastfeeding and weaning

Breastfeeding and weaning are actively studied from evolutionary, medical, and social research perspectives because of their close association with infant mortality, lifetime health, and human population dynamics. Each discipline benefits from an interdisciplinary exchange of knowledge regarding the bases, processes, and consequences of these phenomena. However, current social issues related to breastfeeding and weaning have received little attention from an evolutionary biology perspective. We address this gap by reviewing current social issues related to human breastfeeding and weaning in an evolutionary framework. This approach helps build a conceptual framework with the goal of better understanding ultimate causes of or influences on these current social issues. The six social issues reviewed here fall into three categories: the spatiotemporal constraints of breastfeeding, abuse of breast milk as valuable material, and mismatch in breastfeeding practices. Some of these issues have an evolutionary basis. We analyze the structure of these social issues and discuss their possible solutions in terms of extension of the trade-off theory in evolutionary biology. Our discussion on the current social issues in breastfeeding and weaning highlights the effectiveness of an approach rooted in evolutionary theory and biological anthropology.

What gypsy mothers say about breastfeeding

OBJECTIVE

To know and deepen in the evaluation, and experience of gypsy women with breastfeeding.

METHOD

Qualitative study with an interpretative phenomenological approach, through a focus group with the participation of six mothers of gypsy ethnicity, users of the Fuente de San Luis Health Center in the city of Valencia.

RESULTS

The barriers described by these mothers regarding breastfeeding refer to a lack of family support, an association of breastfeeding to sacrifice and to the dependence of the baby to the breast. From the accounts of these mothers it is perceived, a disinterest in breastfeeding and a lack of confidence in their own bilogy, which together with a low participation in maternal education activities, have meant the barriers that have mostly limited and largely hindered breastfeeding in this group of mothers.

CONCLUSIONS

It would be desirable to implement improvement actions that would pay more attention to promote, protect and support breastfeeding in this group.

Human milk: From complex tailored nutrition to bioactive impact on child cognition and behavior

Human milk is a highly complex liquid food tailor-made to match an infant's needs. Beyond documented positive effects of breastfeeding on infant and maternal health, there is increasing evidence that milk constituents also impact child neurodevelopment. Non-nutrient milk bioactives would contribute to the (long-term) development of child cognition and behavior, a process termed 'Lactocrine Programming'. In this review we discuss the current state of the field on human milk composition and its links with child cognitive and behavioral development. To promote state-of-the-art methodologies and designs that facilitate data pooling and meta-analytic endeavors, we present detailed recommendations and best practices for future studies. Finally, we determine important scientific gaps that need to be filled to advance the field, and discuss innovative directions for future research. Unveiling the mechanisms underlying the links between human milk and child cognition and behavior will deepen our understanding of the broad functions of this complex liquid food, as well as provide necessary information for designing future interventions.

In Vitro Stimulation of Whole Milk Specimens: A Field-Friendly Method to Assess Milk Immune Activity

BACKGROUND

The immune system of milk protects against infections and guides immune system development. A system-level understanding of milk immune activity is critical for research into infant infectious disease risk and lifelong health.

RESEARCH AIM

To describe a protocol to characterize immune activity in human milk via in vitro stimulation for use in population-based (rather than clinical) research.

METHODS

This study proceeded in two phases, each with a cross-sectional design. Human milk specimens were incubated for 24 hr at 37 °C in mammalian cell culture medium with stimuli (e.g., Salmonella enterica) in a CO₂-enriched environment. Immune responses to stimuli were characterized as the change in cytokine: [stimulated]/[baseline]. Predictors of cytokine responses were evaluated with generalized linear models.

RESULTS

Patterns were detectable across mother-child dyads: Interleukin-6 responses to stimuli were generally positively associated with child age and with maternal autoimmune disease.

CONCLUSIONS

Our method allows characterization of pro-inflammatory milk immune activity in vitro in population-based (rather than clinical) research settings. In vitro activity has a system-level interpretation and is likely to be of broad utility in global health research in settings with high infectious disease risk, where understanding the immune system of milk is critical to understanding maternal and child health.

Metabolic Hormone Profiles in Breast Milk From Mothers of Moderate-Late Preterm Infants Are Associated With Growth From Birth to 4 Months in a Sex-Specific Manner

Background: Differing environmental conditions experienced by mother-infant dyads may influence composition of the milk received by the infant. As a consequence, diverse milk compositional profiles may contribute to different postnatal outcomes, especially in infants facing adverse perinatal environments. We investigated whether variability in milk concentrations of key metabolic hormones is associated with different growth outcomes in infants born preterm, a perinatal complication known to impact on infant growth. Methods: Human milk samples were collected from 169 mothers of 191 infants enrolled in the DIAMOND trial, a randomized trial of nutrition for moderate-late preterm infants, at 5 and 10 days postpartum and again at 4 months' corrected age and analyzed for leptin, adiponectin and insulin-like growth factor (IGF)-1. Infant weight and body composition were measured at birth, discharge and 4 months' corrected age. Multiple linear regression models were used to examine correlations between milk hormone concentrations, weight z-scores and body composition at discharge and 4 months' corrected age, and weight gain from birth to 4 months' corrected age. Sex-specific interactions were examined. Results: Higher milk IGF-1 concentrations on day 5 after birth were associated with greater infant fat-free mass at 4 months' corrected age. Milk IGF-1 concentrations at 4 months were positively associated with fat mass and fat-free mass at 4 months in boys but not girls. Milk leptin concentrations on day 5 after birth were positively associated with fat mass at discharge from hospital, but negatively associated with fat mass at 4 months' corrected age. No significant association was found for milk adiponectin concentrations. Conclusion: Milk IGF-1 and leptin concentrations in mothers of moderate-late preterm babies are associated with different growth and body composition through to 4 months' corrected age and these associations are often different in boys and girls. The sex-specific effects of nutrient and hormone exposure during early life in preterm infants warrants further investigation to optimize the nutritional care these infants receive, particularly in hospital, where the same nutrition is provided to boys and girls.

"The sweet and the bitter": mothers' experiences of breastfeeding in the early postpartum period: a qualitative exploratory study in China

Background

In China, the prevalence of exclusive breastfeeding at 6 months was only 20.8%. In promoting breastfeeding for newborns, a number of strategies have been initiated by Chinese government. These actions facilitated a high breastfeeding initiation of 77 to 99.9% in different regions. However, the exclusive breastfeeding rates remained low at 6 months resulting from a high rate of perceived insufficient breast milk and complementary feeding during the early days after childbirth. The aim of this study was to understand the experiences of women in Shenzhen with regard to breastfeeding in the first 6 weeks after giving birth, to identify the facilitators and barriers impacting their breastfeeding decisions and to identify their perceived support needs that might facilitate breastfeeding in the future.

Methods

This was a qualitative exploratory study. Data were collected in November 2018 through semi-structured, face-to-face, in-depth interviews. A purposive sample of early postpartum women was recruited from a postpartum clinic of a tertiary maternal hospital in Shenzhen, China. The dataset was analysed using inductive content analysis.

Results

A total of 22women were interviewed within the first 6 weeks after delivery. Three themes related to breastfeeding were identified from the transcribed interviews: “breastfeeding facilitators,” “breastfeeding barriers,” and “recommendations for breastfeeding promotion.”

Conclusions

Women experienced both joy and suffering in their journey of breastfeeding. Insufficient knowledge of breastfeeding, discomfort, intergenerational disagreements regarding nutritional supplements, and a lack of professional support contributed to difficulties and the threat of discontinuation. A supportive environment for breastfeeding is crucial for women’s decision on exclusive breastfeeding and the psychological wellbeing of breastfeeding women. Interventions that target to promote exclusive breastfeeding should include both new mothers and significant family members. Future studies could test the effectiveness of breastfeeding training for home visit nurses to promote exclusive breastfeeding in the early postpartum.

Typologies of postnatal support and breastfeeding at two months in the UK

There is extensive evidence to suggest that social support improves breastfeeding outcomes. Building on this evidence-base, public health services and interventions aiming to improve breastfeeding rates have primarily targeted informational and emotional support to mothers, reflecting an individual behaviour-change approach. However, mothers exist within a wider social network, and the characteristics of their broader support networks may be an important predictor of breastfeeding outcomes. Here we explore the typologies of postnatal support for mothers in the UK; a population with one of the lowest breastfeeding rates in Europe. Using retrospective data from an online survey (data collection period December 2017 - February 2018), we carry out a latent class regression (n = 432) to identify "clusters" of postnatal support in our data. Mothers in our sample were most likely to report receiving practical and emotional support from partners and maternal grandmothers, and breastfeeding information from health professionals. We identify three distinct typologies of postnatal support: 1) Extensive support, where mothers received support from a wide range of supporters including partners, maternal grandmothers, friends and health professionals, but mothers were the only ones to feed the infant; 2) Family support, where mothers received support from partners and maternal grandmothers, including with infant feeding, but less likely to receive support from health professionals; and 3) Low support, where mothers primarily received support from partners. 94% of women with extensive support were predicted to be breastfeeding at two months, followed by 48% of mothers in the low support group, and 13% in the family support group. Our findings highlight the complexities of family support and its potential impact on breastfeeding, as well as the significance of professional support. Overall, our results hint at the potential value for health professionals to engage with wider family in order to achieve extensive support for mothers.

Bedsharing and Breastfeeding: The Academy of Breastfeeding Medicine Protocol #6, Revision 2019

A central goal of the Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Are mothers less likely to breastfeed in harsh environments? Physical environmental quality and breastfeeding in the Born in Bradford study

We use the United Kingdom's Born in Bradford study to investigate whether women in lower quality environments are less likely to breastfeed. We use measures of physical environmental quality (water disinfectant by-products [DBPs], air pollution, passive cigarette smoke, and household condition) alongside socio-economic indicators, to explore in detail how different exposures influence breastfeeding. Drawing on evolutionary life history theory, we predict that lower environmental quality will be associated with lower odds of initiating, and higher hazards of stopping, breastfeeding. As low physical environmental quality may increase the risk of adverse birth outcomes, which may in turn affect breastfeeding chances, we also test for mediation by gestational age, birthweight, head circumference, and abdominal circumference. Our sample is composed of mothers who gave birth at the Bradford Royal Infirmary in West Yorkshire between March 2007 and December 2010 for whom breastfeeding initiation data was available. Analyses were stratified by the two largest ethnic groups: White British (n = 3,951) and Pakistani-origin (n = 4,411) mothers. After controlling for socio-economic position, Pakistani-origin mothers had lower chances of initiating and higher chances of stopping breastfeeding with increased water DBP exposure (e.g., OR for 0.03-0.61 vs. <0.02 μg/day dibromochloromethane exposure 0.70 [0.58-0.83], HR 1.16 [0.99-1.36]), greater air pollution exposure predicted lower chances of initiation for both ethnic groups (e.g., OR for 10 μg/m³ increase in nitrogen dioxide 0.81 [0.66-0.99] for White British mothers and 0.79 [0.67-0.94] for Pakistani-origin mothers) but also a reduced hazard of stopping breastfeeding for White British mothers (HR 0.65 [0.52-0.80]), and exposure to household damp/mould predicted higher chances of breastfeeding initiation amongst White British mothers (OR 1.66 [1.11-2.47]). We found no evidence that physical environmental quality effects on breastfeeding were mediated through birth outcomes amongst Pakistani-origin mothers and only weak evidence (p < 0.10) amongst White British mothers (exposure to passive cigarette smoke was associated with having lower birthweight infants who were in turn less likely to be breastfed whereas greater air pollution exposure was associated with longer gestations and in turn reduced hazards of stopping breastfeeding). Overall, our findings suggest that there is differential susceptibility to environmental exposures according to ethnicity. Although the water DBP results for Pakistani-origin mothers and air pollution-initiation results for both ethnic groups support our hypothesis that mothers exhibit reduced breastfeeding in poorer quality environments, several physical environmental quality indicators showed null or positive associations with breastfeeding outcomes. We consider physiological explanations for our findings and their implications for life history theory and public health policy.

An Integrated Analysis of Maternal-Infant Sleep, Breastfeeding, and Sudden Infant Death Syndrome Research Supporting a Balanced Discourse

Breastfeeding and the place of sleep for the mother and the infant have been controversial internationally due to reported concerns regarding infant deaths despite the known benefits of exclusive and prolonged breastfeeding, which are increased by breastfeeding at night. The aims of this integrated analysis were to (a) review breastfeeding and maternal and infant sleep research literature via historical, epidemiological, anthropological, and methodological lenses; (b) use this information to determine where we are currently in safeguarding both infant lives and breastfeeding; and (c) postulate the direction that research might take from this point forward to improve our knowledge and inform our policy and practice. Despite well-meaning but unsuccessful campaigns in some countries to dissuade parents from sleeping with their babies, many breastfeeding mothers and caregivers do sleep with their infants whether intentionally or unintentionally. Taking cultural contexts and socio-ecological circumstances into consideration, data supports policies to counsel parents and caregivers on safe sleep practices, including bed-sharing in non-hazardous circumstances, particularly in the absence of parental smoking, recent parental alcohol consumption, or sleeping next to an adult on a sofa. Further research with appropriate methodology is needed to drill down on actual rates of infant deaths, paying close attention to the definitions of deaths, the circumstances of the deaths, and confounding factors, in order to ensure we have the best information with which to derive public health policy. Introduction and use of the concept of "breastsleeping" is a plausible way to remove the negative connotations of "co-sleeping" and redirect ongoing data-driven discussions and education of best practices of breastfeeding and sleep.

Life History theory hypotheses on child growth: Potential implications for short and long-term child growth, development and health

Life history theory integrates ecological, physiological, and molecular layers within an evolutionary framework to understand organisms' strategies to optimize survival and reproduction. Two life history hypotheses and their implications for child growth, development, and health (illustrated in the South African context) are reviewed here. One hypothesis suggests that there is an energy trade-off between linear growth and brain growth. Undernutrition in infancy and childhood may trigger adaptive physiological mechanisms prioritizing the brain at the expense of body growth. Another hypothesis is that the period from conception to infancy is a critical window of developmental plasticity of linear growth, the duration of which may vary between and within populations. The transition from infancy to childhood may mark the end of a critical window of opportunity for improving child growth. Both hypotheses emphasize the developmental plasticity of linear growth and the potential determinants of growth variability (including the role of parent-offspring conflict in maternal resources allocation). Implications of these hypotheses in populations with high burdens of undernutrition and infections are discussed. In South Africa, HIV/AIDS during pregnancy (associated with adverse birth outcomes, short duration of breastfeeding, and social consequences) may lead to a shortened window of developmental plasticity of growth. Furthermore, undernutrition and infectious diseases in children living in South Africa, a country undergoing a rapid nutrition transition, may have adverse consequences on individuals' cognitive abilities and risks of cardio-metabolic diseases. Studies are needed to identify physiological mechanisms underlying energy allocation between biological functions and their potential impacts on health.

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Public health concerns associated with infant feeding have prompted the need to increase breastfeeding rates. To do so, initiatives have been implemented and proven successful in raising breastfeeding initiation rates. However, continued breastfeeding according to official recommendations remains scarce and many mothers feel emotionally burdened by their experience. This commentary thus raises the question about the effects of breastfeeding promotion on the well-being of families and takes a critical look at the strategies being put in place. A conceptual model as well as empirical evidences help better understand the balancing act underlying the decisions related to infant feeding and the risks of promoting breastfeeding without providing adequate support. The context of the transition towards a breastfeeding culture requires setting up services adapted to parents' current needs. An approach taking into account their satisfaction and reinforcing their self-efficacy must be adopted, namely through a more thorough implementation of the Baby-Friendly Initiative. Allocating resources allowing for proper enactment of this approach is essential to increase breastfeeding while ensuring families' well-being.

Conflict or congruence? Maternal and infant-centric factors associated with shorter exclusive breastfeeding durations among the Tsimane

Six months of exclusive breastfeeding (EBF) is considered optimal for infant health, though globally most infants begin complementary feeding (CF) earlier-including among populations that practice prolonged breastfeeding. Two frameworks for understanding patterns of early CF emerge in the literature. In the first, maternal and infant needs trade-off, as "maternal-centric" factors-related to time and energy demands, reproductive investment, cultural influences, and structural barriers- favor supplanting breastfeeding with earlier and increased CF. A second framework considers that "infant-centric" factors-related to infant energetic needs-favor CF before six months to supplement breastfeeding. We apply these two frameworks in examining early CF among the Tsimane-a high-fertility, high-mortality, forager-horticulturalist population residing in the Bolivian Amazon. Data were collected from a mixed-longitudinal sample of 161 Tsimane mother-infant pairs from August 2012-April 2013. Tsimane mothers generally reported introducing CF because of perceived infant needs. However, CF is introduced with continued intensive breastfeeding, and generally coupled with premastication. Risks of earlier CF relative to the minimum hazard (estimated at 5 births) were elevated for lower and higher parity mothers, but were significantly greater only after 9 births. Seventeen percent of mothers reported introducing CF because of low milk supply. Introducing CF because of low milk was most common from 0 to 3 months of age and among higher parity mothers, which may reflect physiological constraints. Maternal reproductive trade-offs and perceived infant needs may help explain the low prevalence of EBF to six months among other populations in which breastfeeding is not structurally or culturally constrained.

Exploring Maternal Perceptions of Infant Sleep and Feeding Method Among Mothers in the United Kingdom: A Qualitative Focus Group Study

BACKGROUND

In a context with strong rhetorical support for breastfeeding in the health system, yet extremely low rates of breastfeeding after hospital discharge, U.K. women's decisions about infant feeding reflect the reality of competing priorities in their lives, including obtaining adequate sleep. Popular wisdom in the U.K. tightly links breastfeeding and inadequate night-time sleep. Mothers are advised by peers and family to introduce formula or solid foods to infants to promote longer sleep.

OBJECTIVES

The first objective of this study was to investigate women's understandings of the nature of infant sleep and their perceptions of links between infant feeding method and sleep. The second was to explore how these perceptions influence infant feeding and sleep practices. Underpinning our work is the understanding that infant care choices result from trade-offs by which mothers strive to balance infant- and self-care.

METHODS

We conducted seven focus groups with mothers of infants in two regions of the U.K. Verbatim transcripts were thematically coded and emergent themes were identified.

RESULTS

We found clearly diverging narratives between breastfeeding and formula-feeding mothers. Breastfeeding mothers viewed the fragmentary nature of infant sleep as natural, while mothers who were formula feeding felt this was a problem to be fixed.

CONCLUSIONS AND PRACTICE

The strategies used to promote infant and maternal sleep in each group were aligned with their underlying perception of how infant sleep works. Maternal perceptions of the nature of infant sleep and its relation to infant feeding method impact infant care practices in the first year of life.

Who pays for the health benefits of exclusive breastfeeding? An analysis of maternal time costs

BACKGROUND

The benefits of exclusive breastfeeding, including public health cost savings, are widely recognized, but breastfeeding requires maternal time investments.

OBJECTIVE

This study investigates the time taken to exclusively breastfeed at 6 months compared with not exclusively breastfeeding.

METHODS

Time use data were examined from an Australian survey of new mothers conducted during 2005-2006. Data from 139 mothers with infants age 6 months were analyzed using chi-square tests of independence to examine socioeconomic and demographic characteristics and 2-sided t tests to compare average weekly hours spent on milk feeding, feeding solids, preparing feeds, and the total of these. The comparison was of exclusively breastfeeding mothers with other mothers. We also compared exclusively breastfeeding with partially breastfeeding and formula feeding mothers using a 1-way between-groups analysis of variance (ANOVA).

RESULTS

The exclusively breastfeeding (vs other) mothers spent 7 hours extra weekly on milk feeding their infants but 2 hours less feeding solids. These differences were statistically significant. ANOVA revealed significant differences between exclusively breastfeeding mothers, breastfeeding mothers who had introduced solids, and mothers who fed any formula, in time spent feeding milk, and solids, and preparing feeds.

CONCLUSION

Exclusive breastfeeding is time intensive, which is economically costly to women. This may contribute to premature weaning for women who are time-stressed, lack household help from family, or cannot afford paid help. Gaining public health benefits of exclusive breastfeeding requires strategies to share maternal lactation costs more widely, such as additional help with housework or caring for children, enhanced leave, and workplace lactation breaks and suitable child care.

Postnatal unit bassinet types when rooming-in after cesarean birth: implications for breastfeeding and infant safety

BACKGROUND

Postnatal unit rooming-in promotes breastfeeding. Previous research indicates that side-cars (3-sided bassinets that lock onto the maternal bed frame) facilitate breastfeeding after vaginal birth more than stand-alone bassinets (standard rooming-in). No study has previously investigated side-car bassinet use after cesarean, despite the constraints on maternal-infant interactions that are inherent in recovery from this birth mode.

OBJECTIVE

To test the effect of the side-car bassinet on postnatal unit breastfeeding frequency and other maternal-infant behaviors compared to a stand-alone bassinet following cesarean birth.

METHODS

Participants were recruited and prenatally randomized to receive the side-car or stand-alone bassinet for their postnatal unit stay between January 2007 and March 2009 in northeastern England. Mother-infant interactions were filmed over the second postpartum night. Participants completed face-to-face interviews before and after filming. The main outcome measures were infant location, bassinet acceptability, and breastfeeding frequency. Other outcomes assessed were breastfeeding effort, maternal-infant contact, sleep states, midwife presence, and infant risk.

RESULTS

Differences in breastfeeding frequency, maternal-infant sleep overlap, and midwife presence were not statistically significant. The 20 dyads allocated to side-car bassinets breastfed a median of 0.6 bouts/ hour compared to 0.4 bouts/hour for the 15 stand-alone bassinet dyads. Participants expressed overwhelming preference for the side-car bassinets. Bed sharing was equivalent between the groups, although the motivation for this practice may have differed. Infant handling was compromised with stand-alone bassinet use, including infants positioned on pillows while bed sharing with their sleeping mothers.

CONCLUSIONS

Women preferred the side-car, but differences in breastfeeding frequency were not statistically significant. More infant risks were observed with stand-alone bassinet use.