Weight as a Bio-Social Filter of the Proximate Determinants of Fertility

Michelle Frisco, Pennsylvania State University
Kristin Burnett, Pennsylvania State University

A woman’s weight is located theoretically at the intersection between internal biological factors that influence her fertility and external social, economic and cultural factors that also influence her fertility. Integrating research from multiple disciplines, we use a proximate determinants framework to develop and test hypotheses about these pathways. Data on fertility histories come from nulliparous women sampled in the National Longitudinal Survey of Youth 1979-1997 and Longitudinal Study of Adolescent Health 1994/5-2000/1. Findings suggest that obese women in both cohorts experience later and fewer pregnancies and births. At the same time, obesity is associated with a reduced likelihood of abortion in the younger and more recent birth cohort, while in the older and less contemporary birth cohort, overweight increases the likelihood of miscarriage or stillbirth. We discuss the implications of these findings for future trends in U.S. fertility during an era when the prevalence of obesity is on the rise.