The effect of first interbirth interval on women's poverty at midlife

Understanding the relationship between childbearing and socioeconomic status could help explain one mechanism by which the United States’ gender disparity in poverty comes to exist. However, measuring the relationship between childbearing and socioeconomic status is complicated by the very high prevalence of childbearing among women and multiple sources of endogeneity in the characteristics of childbearing that do vary. Focusing on the timing of childbearing, I use miscarriage to construct an instrument for delivery and build a counterfactual condition for having a short temporal space between births. Using this approach with data from the National Longitudinal Survey of Youth 1979, I estimate the effect on midlife poverty of having first and second births within 24 months of each other. My results indicate that these short interbirth intervals are causally related to increased midlife poverty. The results are robust to a variety of alternate specifications of counterfactual conditions and estimation methods.