Impact of Marriage on Birth Outcomes: Pregnancy Risk Assessment Monitoring System, 2012-2014.

Marriage has been associated with improved pregnancy outcomes. However, as Americans become increasingly accepting of pregnancy and childbearing outside of marriage, many believe the father can support the mother without the parents being married. Some question whether the present normalization of childbearing outside of marriage will negate the protective effect of marriage on pregnancy outcomes. Data from the Centers for Disease Control and Prevention Pregnancy Risk Assessment Monitoring System were used to obtain data from a sample of 138,118 live singleton deliveries from 2012 to 2014. Odds ratios were compared between married and unmarried mothers for outcomes of preterm delivery, a small for gestational age infant, neonatal intensive care unit admission, vaginal delivery, and breastfeeding initiation. Logistic regression analyses were used to adjust for maternal age, maternal and paternal race, maternal medical comorbidities, maternal smoking status, and receipt of Medicaid. Adjusted odds ratios (AOR) showed married women had a lower risk of preterm delivery (AOR = .877, 95% confidence interval [CI; .811-.948]), a small for gestational age baby (AOR = .838, 95% CI [.726-.967]), and a neonatal intensive care admission (AOR = .808, 95% CI [.754-.866]). Women who were married were more likely to have a vaginal delivery (AOR = 1.144, 95% CI [1.085-1.211]) and to initiate breastfeeding (AOR = 1.601, 95% CI [1.490-1.719]). These data demonstrate that despite a normalization in society of childbearing outside of marriage, there continues to be an association of marriage with improved birth outcomes. Marriage is associated with a lower risk of preterm delivery, small for gestational age infants, and neonatal intensive care unit admission. These differences persist even after correcting for potentially confounding socioeconomic factors.