Pregnancy Complicated With Hepatitis B Virus Infection and Preterm Birth: A Retrospective Cohort Study

Background: We aimed to investigate whether maternal chronic hepatitis B virus (HBV) infection affects preterm birth（PTB) in pregnant women. Methods: : We retrospectively analyzed HBV-infected and non-infected pregnant women attending antenatal care at Fujian Provincial Maternity and Child Health Hospital, Fuzhou, China between January 1, 2016 to December 31, 2018. Participants were divided into HBV infection (n = 1302) and control (n = 12813) groups. We compared baseline data, pregnancy and perinatal complications, and preterm delivery outcomes between groups and performed subgroup comparisons and multiple logistics regression analysis to adjust for confounding factors. Results: : The incidence of PTBs before 37 weeks was similar between the groups. PTBs before 34 weeks were significantly more among the HBV infection group than among the controls (1.6% VS. 0.8% ; P = 0.003) After adjusting for confounding factors through logistics regression, HBV infection was found to be an independent PTB risk factor before 34 weeks gestation (adjusted odds ratio 1.796; 95% confidence interval[1.071, 3.012]). According to the subgroup analysis based on whether hepatitis B e-antigen (HBeAg) was positive and whether alanine aminotransferase (ALT) levels were normal during the second trimester, PTB was more frequent in HBeAg negative HBV infection before 34 weeks than among controls(1.8% VS. 0.8%). The PTB rate for pregnant women with normal ALT and HBV infection before 34 weeks was higher than that of the controls (1.6% VS. 0.8%) Conclusion: HBV infection is an independent risk factor for PTB before 34 weeks. Comprehensive programs focusing on pregnant women with HBV infection would reduce the incidence of adverse outcomes.