Maternal and fetal health effects of working during pregnancy

Abstract

We provide some of the first empirical evidence of maternal and fetal health effects of working during pregnancy by using a unique dataset from the New Jersey Department of Health that includes information not only on pregnancy and birth outcomes but also on maternal employment. We match the mother’s occupation with the Metabolic Equivalent of Task, provided by the Census Occupational Classification System and used as a measure for the strenuousness of the work activities performed. Focusing on an empirical setting where laws regarding reasonable accommodations for pregnant women are already in place, we still find consistent and robust evidence that working in a relatively more strenuous job during pregnancy raises the likelihood of an adverse birth outcome, specifically fetal macrosomia, by about 1.5 percentage points. While there are no statistically or economically significant effects on other birth outcomes, our finding of a significant increase in fetal macrosomia nevertheless highlights a possible deficiency of existing accommodation laws intended to protect pregnant workers. In addition, our study indicates an under-studied link between gestational diabetes (a known risk factor for fetal macrosomia) and intensive physical activities at work during pregnancy, potentially mediated by disrupted sleep due to greater work intensity.