Doctoral Dissertation Research: Maternal Energetic Strategies During Human Pregnancy

Human newborns are relatively altricial – or, developmentally immature – in many ways compared to those of our closest living relatives. This may be due to evolutionary constraints on the length of human gestation, specifically, energetic costs that human mothers may be unable to bear beyond nine months. An approach centered on energetics provides a way to investigate constraints of human pregnancy from a physiological perspective, which offers an important complement to more traditional and anatomically focused views on understanding pregnancy length. This doctoral dissertation research project pairs and evaluates daily physical activity and energy expenditure measures in highly active pregnant women, and further builds out a deeper understanding of these processes with a study design that includes repeated measures on the same women throughout their pregnancies. The results of this research contribute to the study of the evolution of human pregnancy, and to the urgent need to understand the physiology of human pregnancy and birth, due to the high rates of poor maternal and infant health outcomes in the United States and globally. This project tests the associations between daily physical activity, energy expenditure, gestational weight gain, and pregnancy outcomes in a highly active sample of pregnant mothers. Gestational weight gain and maternal metabolic parameters are measured twice during pregnancy, and physical activity data are collected daily. Measurements of total daily energy expenditure, basal metabolic rate, and body composition are used to test associations between maternal physical activity, metabolic parameters, and pregnancy outcomes. Results address the maternal metabolic limits hypotheses regarding pregnancy length in relationship to maternal activity levels and can inform strategies that promote physical activity and healthy pregnancy outcomes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.