Protocol for the Emory University African American maternal stress and infant gut microbiome cohort study

The microbial population of the human gut (the gut microbiome) is an integral cog in the bidirectional communication axis that exists between the gastrointestinal tract and the central nervous system. African American infants disproportionately experience multiple, overlapping vulnerabilities such as preterm birth and formula rather than breast feeding that may disrupt the development of the infant microbiome. African American infants also are more likely to have mothers affected by chronic stress both pre- and post-natally. Perhaps relatedly, African American offspring are disproportionately affected by neurodevelopmental delays. Taken together, these findings suggest that one important mechanism that may link prenatal and postnatal stress and African American infant brain development is the composition of the infant microbiome.

In our ongoing longitudinal study, Maternal Stress and the Gut-Brain Axis in African American Infants (R01MD009746), we investigate associations between maternal prenatal and postnatal stress and the composition of the infant gut microbiome, in relation to cognitive and social-emotional development. We aim to recruit 300 African American mother-infant dyads, contingent on the mother's previous participation in an associated prenatal cohort study: Biobehavioral Determinants of the Microbiome and Preterm Birth in Black Women (R01NR014800). Following enrollment, we assess infants at 1-week, and 3-, 6-, 12-and 18-months to collect: standardized assessments of infant neurocognitive and social-emotional development; questionnaire measures of infant feeding and health; observational data on maternal-infant interactions; maternal reports of postnatal stress; blood and saliva samples to evaluate maternal and infant psychoneuroimmunologic (PNI) function; and infant stool samples to characterize acquisition and trajectory of gut microbiome composition. Genetic variants of the major histocompatibility complex that may influence gut microbiome composition are also being evaluated.

This rich data set will allow future consideration of risk and protective factors that influence neurodevelopment in African American infants who are exposed to varying levels of prenatal and early life stress. Evidence for a mechanistic role of the microbiome would provide a framework for future clinical evaluations of preventative interventions (e.g., probiotics, culturally-appropriate breastfeeding campaigns) that could potentially improve the health and development of African American children in infancy and across the lifespan.