Few studies have assessed the risk of adverse pregnancy outcomes in women with multiple sclerosis (MS). We used 2 large US administrative databases, the Truven Health MarketScan Database (2011-2015; Truven Health Analytics Inc., Ann Arbor, Michigan) and the Nationwide Inpatient Sample (2007-2011), to identify delivery cohorts. MS and pregnancy outcomes (infections, cesarean delivery, preterm delivery, poor fetal growth, preeclampsia, chorioamnionitis, postpartum hemorrhage, stillbirth, and infant malformations) were identified during pregnancy and at delivery. We calculated adjusted risk ratios according to MS status and relapse(s) in the year before delivery. Among over 5 million pregnancies, we identified 3,875 pregnancies in women with MS. Women with MS had an increased risk of infections during pregnancy (Truven Health: adjusted risk ratio (aRR) = 1.22, 95% confidence interval (CI): 1.16, 1.27) and preterm delivery (Truven Health: aRR = 1.19 (95% CI: 1.04, 1.35); Nationwide Inpatient Sample: aRR = 1.30 (95% CI: 1.16, 1.44)). The risks of other outcomes were similar for women with and without MS. In the Truven Health database, risk ratios for the pregnancy outcomes in women experiencing relapses versus those without relapses were between 0.9 and 1.4, and confidence intervals overlapped the null. Overall, women with MS had an increased risk of infections and preterm delivery; however, their risks for other adverse pregnancy outcomes were not elevated. Disease activity before delivery was not a strong predictor of outcomes.