Maternal HBsAg carriers and adverse pregnancy outcomes: a hospital-based prospective cohort analysis.

It is not clear whether chronic hepatitis B virus (HBV) infection during pregnancy can increase the risk of adverse pregnancy outcomes for both mothers and neonates. We conducted a hospital-based prospective cohort study on pregnant women (PW) and used an analysis strategy that was guided by directed acyclic graphs (DAGs). Maternal characteristics and major adverse pregnancy outcomes were collected both from questionnaires and hospital-based electronic medical records. Serum hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) status were determined. In total, 3329 of the 3416 pregnant women who received routine antenatal care in a hospital setting at baseline, including 346 HBsAg carriers, were available for analysis. Maternal HBsAg carrier status was associated with an increased risk of intrahepatic cholestasis pregnancy [aOR (adjusting odds ratio) = 1.70; 95% CI (confidence interval) = 1.16-2.49], premature rupture of the membranes (aOR = 1.38; 95% CI = 1.00-1.89) and large for gestational age birth aOR = 1.67; 95% CI = 1.17-2.39). The risk of intrahepatic cholestasis remained in pregnant women with either HBeAg-positive (aOR = 2.96; 95% CI = 1.33-6.62) or HBeAg-negative (aOR = 1.52; 95% CI =1.00-2.32)] status; notably, only maternal HBeAg-negative status was associated with a higher risk of large for gestational age birth (aOR = 1.91; 95% CI = 1.33-2.76). Our results implied that chronic HBV infection during pregnancy may increase the risk of intrahepatic cholestasis of pregnancy, premature rupture of membranes and large for gestational age pregnancies.