Maternal and Fetal Health Effects of Working during Pregnancy

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. We find robust evidence that working in a relatively more strenuous job during pregnancy raises the likelihood of fetal macrosomia by about 1.5 percentage points. There are no statistically or economically significant effects on other birth outcomes. Our study further 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.