Maternal hepatitis B surface antigen status and incidence of pre-eclampsia

The relationship between chronic hepatitis B virus (HBV) infection with atherosclerosis and cardiovascular disorders remains unclear, and the impact of maternal HBV infection on the development of pregnancy-induced hypertension (PIH) and pre-eclampsia (PE) is also controversial. This retrospective cohort study was conducted to examine the relationship between maternal hepatitis B surface antigen (HBsAg) status with PIH and PE in singleton pregnancies that delivered at 24 weeks of gestation and beyond. Among the 86 537 cases in the cohort, 10% were HBsAg positive, and overall 2.0% had PIH, of whom 56.3% developed PE. HBsAg-positive women had higher weight and body mass index (BMI), but lower incidences of advanced age, nulliparity, PIH (1.6% vs 2.0%, P = 0.007) and PE (0.8% vs 1.1%, P = 0.005). On multiple logistic regression analysis adjusting for the effects of nulliparity, advanced age, high BMI, and underlying renal, cardiac and autoimmune diseases, HBsAg carriage was associated with significantly reduced incidence of PIH (aOR 0.79, 95% CI 0.66-0.95) and PE (aOR 0.71, 95% CI 0.56-0.91). Our results indicate that maternal HBsAg carriage is independently associated with reduced PE. As chronic HBV infection alters the immune response of the individual, our observation could be related to enhanced maternal immunotolerance of the foetus and hence a reduction in the incidence of PE. The implications of our findings on the long-term health outcome of the infected women, from cardiovascular morbidity to malignancies, warrant further studies.