Breastfeeding and Breast Milk Research Activities and Advances

Several NICHD organizational units (OUs) support and conduct research on breastfeeding and breast milk. Many of these efforts overlap and require trans-NICHD and trans-NIH collaboration. The following is only a summary of some of these efforts.

Pediatric Growth and Nutrition Branch (PGNB) research on breastfeeding is part of a larger research program on nutrition that uses a systems approach to incorporate biological, environmental, and other critical components as integral to public health. This program also explores nutritional variables, including those specific to breastfeeding, in both domestic and international contexts. Some of the PGNB projects related to breastfeeding include:

PGNB Study Results: Longer Breastfeeding Does Not Protect Against Childhood Obesity

An increasing number of children worldwide are overweight or obese. Overweight and obese children are at a higher risk for a range of medical problems, including type 2 diabetes. Previous studies have indicated that children who were breastfed were less likely to become obese in early life, compared with children who were fed with infant formula. But these studies were observational, making it hard to rule out other causal effects. To better investigate a possible link between breastfeeding and obesity, researchers followed up on a large clinical trial in Belarus that tested whether an intervention promoted breastfeeding in infants. Women who received the intervention breastfed their infants longer and more exclusively than women in the control group. The researchers went back to 13,800 of these infants when they were 11.5 years of age. Children who were breastfed longer or more exclusively were just as likely to be obese or overweight as children from the control group. The children also had similar levels of insulin-like growth factor, which regulates childhood growth. The researchers concluded that although breastfeeding has many other advantages, it is unlikely to curb increasing rates of obesity. (PMID: 23483175)

  • Improving knowledge of maternal-fetal and newborn nutrition, particularly for preterm infants, low-birth-weight (LBW) infants, and infants in resource-poor areas;
  • Elucidating the nutritional and bioactive components of breast milk, such as iron, and how these influence the duration of exclusive breastfeeding and the timing of introduction of supplemental or complementary foods;
  • Understanding the role of breast milk and its components in gastrointestinal immunity, prevention of respiratory disease, and prevention and treatment of infections and inflammation;
  • Identifying biomarkers for exposure, status, and function of vitamin D, zinc, and other nutrients and micronutrients and defining the long-term impacts of nutritional deficiency during infancy;
  • Exploring the nutritional needs of women with HIV/AIDS and how best to safely wean their infants to minimize exposure to the disease while still providing optimal nutrition, especially in resource-poor areas; and
  • Contributing scientific expertise to the World Health Organization (WHO), the United Nations World Food Programme, the President's Emergency Plan for AIDS Relief (PEPFAR), the NIH Office of AIDS Research, and other groups' guidelines and best practice recommendations on infant feeding and nutrition.

The Institute's Pregnancy and Perinatology Branch (PPB) supports basic and clinical studies aimed at understanding the etiology, pathophysiology, therapy, and follow-up of health during the perinatal and neonatal periods, as well as research on in utero conditions and their influence on health outcomes. Among the PPB's projects within this context related to breastfeeding are:

PPB Study Results: Depression During Pregnancy May Affect the Nutritional Quality of Breast Milk

Many women experience depression during pregnancy and in the early months after childbirth. Previous studies showed a link between docosahexaenoic acid (DHA) and positive mental health. DHA is also known to be important for optimal brain development in the growing fetus and in infants. Based on these earlier findings, researchers conducted a study to examine whether symptoms of depression during pregnancy affect the concentration of DHA in breast milk. Researchers conducted a survey of 287 women to assess whether they experienced depressive symptoms. Breast milk samples were collected from the same women 4 months after childbirth to measure the concentration of DHA. The results from the study showed that women who reported depressive symptoms in the first 20 weeks of pregnancy had lower concentrations of DHA in their breast milk. The same association was not found in women who reported depressive symptoms later in pregnancy. Because depression prior to pregnancy was not measured, it was unclear whether the women in this study were experiencing chronic depression or temporary depression due to stress or hormonal changes associated with pregnancy. However, because levels of DHA measured in breast milk are reflective of long-term influences on the body to store DHA over time, low levels of DHA in breast milk are likely associated with chronic depression. (PMID: 22223516)

PPB Podcast: Lactation consultants increase breastfeeding rate

In an NICHD Research Developments podcast, Dr. Karen Bonuck, professor of women's health and family and social medicine at the Albert Einstein College of Medicine, discusses her research on interventions to increase breastfeeding in low-income and multi-ethnic women. Her study, supported by NICHD and published in the American Journal of Public Health, found that women who were visited by lactation consultants were three times more likely to breastfeed for 3 months compared to women who received usual care. The key, explains Dr. Bonuck, is integrating the lactation consultants into women's routine primary care. Lactation consultants approached women while they were waiting to attend prenatal visits and later visited women in their homes. (PMID: 24354834)

PPB Study Results: What Predicts Intent to Breastfeed Exclusively?

All major medical organizations endorse exclusive breastfeeding for the first 6 months after birth. However, only 13.3% of infants in the United States are exclusively breastfed through 6 months, with major differences in rates by maternal race, ethnicity, education, and income. Women who, while pregnant, form an intention to breastfeed their baby are most likely to do so. Scientists measured the association between intentions to exclusively breastfeed and knowledge of infant health benefits, feeding guidelines, and comfort related to breastfeeding in social settings. The study was conducted with a group of lower-income, ethnically diverse urban women. The results showed that 46% of women in the study intended exclusive breastfeeding, an equal proportion (46%) intended to use mixed feeding, and 8% intended to use formula feeding exclusively. Maternal knowledge about infant health benefits, as well as comfort with breastfeeding in social settings, was directly related to intention to exclusively breastfeed, and to breastfeed exclusively for longer periods of time. (PMID: 21342016)

Scientists analyzed data from 1,636 women who were part of the Community Child Health Network, an NICHD-sponsored project. They found that Spanish-speaking Hispanic mothers were the most likely to initiate breastfeeding, followed by English-speaking Hispanic mothers and white mothers. Black mothers are the least likely to initiate and maintain breastfeeding. In all ethnic groups, feeding with formula in the hospital led to a shorter time spent breastfeeding. These factors must be considered when trying to reduce racial and ethnic disparities in breastfeeding. (PMID: 27405771)

  • Studies on the optimal timing of breastfeeding initiation, especially in resource-poor countries, and the effects on infant health outcomes, including infant mortality;
  • Research on the effects of breastfeeding on brain development, specifically development of the medullary raphe of the brainstem and the serotonin systems, and its mechanisms for reducing the risk for Sudden Infant Death Syndrome;
  • Investigations of how breast milk improves neurodevelopmental and other outcomes for neonates, including extremely LBW (ELBW) infants and preterm infants; and
  • Research on breast milk and its effects on severity of and treatment for certain newborn diseases, such as necrotizing enterocolitis, retinopathy of prematurity, and jaundice.

The Maternal and Pediatric Infectious Disease Branch conducts and supports research on breast milk and breastfeeding within the context of HIV/AIDS infection and transmission. This research includes not only studies of the prevention of mother-to-child transmission (MTCT) of HIV/AIDS through a combination of limited duration of breastfeeding and medication interventions, but also the biological mechanisms by which MTCT occurs via breast milk. Additional studies examine the conditions that enhance or reduce the chance of transmission through breast milk, such as viral load and the number of mammary cells infected with HIV. Branch studies also aim to provide evidence about the best practices for breastfeeding, formula feeding, weaning, and supplementation for populations affected by HIV/AIDS. This research is conducted both domestically and abroad and includes partnerships and collaborations with other NIH Institutes and Offices, the WHO, PEPFAR, and other agencies and organizations in the United States and elsewhere.

The NICHD Population Dynamics Branch supports research on breastfeeding within the context of its social and societal impacts. Some of these studies aim to understand the home and socioeconomic factors that influence breastfeeding decisions, while other efforts aim to quantify the effects of workplace and public policies on breastfeeding and breastfeeding duration. This work also examines the potential impact of breastfeeding on current and future health and productivity in population representative samples.

Researchers in the NICHD Division of Intramural Population Health Research also conduct research on breastfeeding and breast milk. These studies include (but are not limited to) the effects of maternal nutrition and malnutrition on breast milk composition and subsequent effects on fetal and infant nutrition. Additional research examines the factors that influence breastfeeding decisions, particularly among those in at-risk groups, including African American mothers who live in low-income areas, as well as the long-term effects of breastfeeding on chronic diseases, such as obesity.

Through its Obstetric and Pediatric Pharmacology and Therapeutics Branch (OPPTB), NICHD also studies the effects of certain drugs on pregnancy and neonatal outcomes. Among the studies supported by the OPPTB are those that examine whether certain medications are transmitted via breast milk and their effects on infant development.

As explained above, NICHD OUs collaborate with each other, with NIH Institutes and Centers, and with other governmental and non-governmental organizations in the United States and worldwide. Some of these partnership and activities are described below.

  • The NICHD PPB collaborated with the Centers for Disease Control and Prevention and the U.S. Food and Drug Administration to conduct the Infant Feeding Practices II Survey aimed at examining infant feeding practices, including breastfeeding, among a large cohort of women and the impacts of these practices on infant health. 
  • The Neonatal Research Network (NRN), supported through the PPB, investigates the safety and efficacy of treatment and management strategies for newborn infants. The NRN has led several of the PPB's efforts on breastfeeding and neurodevelopmental outcomes for ELBW infants and on nutritional management of preterm, LBW, and ELBW infants.

NICHD also participated in activities related to the Surgeon General's Call to Action to Support Breastfeeding.

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