INTRODUCTION: Hepatitis B virus (HBV) infection acquired during pregnancy can pose a risk to the infant at birth that can lead to significant and lifelong morbidity. Hepatitis B vaccine (HepB) is recommended for anyone at increased risk for contracting HBV infection, including pregnant women. Limited data are available on the safety of HepB administration during pregnancy. OBJECTIVES: To assess the frequency of maternal HepB receipt among pregnant women and evaluate the potential association between maternal vaccination and pre-specified maternal and infant safety outcomes. METHODS: We examined a retrospective cohort of pregnancies in the Vaccine Safety Datalink (VSD) resulting in live birth outcomes from 2004 through 2015. Eligible pregnancies in women aged 12-55years who were continuously enrolled from 6months pre-pregnancy to 6weeks postpartum in VSD integrated health systems were included. We compared pregnancies with HepB exposure to those with other vaccine exposures, and to those with no vaccine exposures. High-risk conditions for contracting HBV infection were identified up to one-year prior to or during the pregnancy using ICD-9 codes. Maternal and fetal adverse events were also evaluated according to maternal HepB exposure status. RESULTS: Among over 650,000 pregnancies in the study period, HepB was administered at a rate of 2.1 per 1000 pregnancies (n=1399), commonly within the first 5weeks of pregnancy. Less than 3% of the HepB-exposed group had a high-risk ICD-9 code indicating need for HepB; this was similar to the rate among HepB unvaccinated groups. There were no significant associations between HepB exposure during pregnancy and gestational hypertension, gestational diabetes, pre-eclampsia/eclampsia, cesarean delivery, pre-term delivery, low birthweight or small for gestational age infants. CONCLUSIONS: Most women who received maternal HepB did not have high-risk indications for vaccination. No increased risk for the adverse events that were examined were observed among women who received maternal HepB or their offspring.