Date of Award

Spring 1-1-2017

Document Type

Thesis

Degree Name

Master of Arts (MA)

First Advisor

Robin M. Bernstein

Second Advisor

Darna Dufour

Third Advisor

Joanna Lambert

Abstract

Maternal stress during pregnancy, whether physical, immunological, or psychosocial, influences maternal physiology and can leave the fetus vulnerable to adverse effects of maternal and environmental stress. The Developmental Origins of Health and Disease hypothesis suggests that the gestational period, through environmental and maternal signals, has significant impact on the health outcomes for the fetus, infant, and later adult. Environmental and maternal signals can be translated to the developing fetus through epigenetic mechanisms, changes in cell cycle regulation and tissue differentiation, and endocrine pathways.

The Gambia is characterized by strong seasonality that, in rural areas, influences maternal workload, food availability, and disease burden. Researchers have linked season of conception and birth to epigenetic modifications, patterns of growth, and adult mortality. While the impact of psychosocial stress on infant health has not been explored in The Gambia, the various forms of stress (e.g. nutritional and environmental) during pregnancy have the potential to affect maternal cortisol and increase the risk of negative birth and infant outcomes.

This thesis explores the influences of seasonality and maternal sociodemographic factors on fetal and infant growth (N=204) in rural Gambia. Hair collected from neonates one week postnatally was processed and analyzed for cortisol. Fetal hair cortisol concentrations (fHCCs) were expected to be higher during the wet season and among low SES mother-infant pairs; significant elevations or depressions in fHCCs were expected to impact growth. Results suggest that fHCCs are not overtly influenced by maternal factors, season of conception or season of birth; however, there were significant associations between male infant growth and fHCCs. Males with high fHCCs had lower weight, weight-for-height, and mid-upper-arm circumference z-scores at 12 months. A significant association was also found between gestational age and fHCCs such that males with higher fHCCs were born at earlier gestational ages, and female infants with high fHCC were born at later ages compared to low fHCC counterparts. Overall, males seem more sensitive to the effects of elevated fetal hair cortisol than females. These findings suggest that male infants in Gambia may be more immediately vulnerable to intrauterine stress and that there could be lasting consequences on development.

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