Maternal Hepatitis B Infection and Pregnancy Outcomes in the United States: A Population-Based Cohort Study

BACKGROUND: Hepatitis B virus (HBV) infection in pregnancy has been associated with risk of adverse maternal and infant outcomes in highly endemic settings, but this association is not well characterized in the United States. METHODS: We conducted a retrospective population-based cohort study in Washington State using linked birth certificate and hospital discharge records from 1992–2014. Among pregnant women with hepatitis B (n = 4391) and a hepatitis B–negative group (n = 22 410), we compared the risk of gestational diabetes, pre-eclampsia, eclampsia, placenta previa, preterm delivery, low birthweight, small for gestational age, and large for gestational age using multivariate logistic regression. RESULTS: Hepatitis B–infected pregnant women were more likely to be Asian (61% vs 8%, P < .001), foreign-born (76% vs 23%, P < .001), and older in age (77% vs 64% ≥26 years, P < .001). They were less commonly overweight or obese (33% vs 50%, P < .001). There was a lower risk of small for gestational age infants among HBV-infected women (adjusted RR [aRR], 0.79; 95% confidence interval [CI], 0.67–0.93). The risk of other adverse outcomes was not significantly different between hepatitis B–infected and –negative women (gestational diabetes: aRR, 1.11; 95% CI, 0.92–1.34; pre-eclampsia: aRR, 1.06; 95% CI, 0.82–1.35; eclampsia: aRR, 2.31; 95% CI, 0.90–5.91; placenta previa: aRR, 1.16; 95% CI, 0.35–3.84; preterm delivery: aRR, 1.15; 95% CI, 0.98–1.34; low birth weight: aRR, 1.08; 95% CI, 0.90–1.29; large for gestational age: aRR, 1.01; 95% CI, 0.82–1.24). CONCLUSIONS: In a low-burden setting in the United States, hepatitis B infection was not associated with adverse pregnancy outcomes.