Association of chronic hepatitis B virus infection with preterm birth: our experience and meta-analysis

Objectives: To assess the association of chronic hepatitis B virus (HBV) infection with preterm birth (PTB). Methods: A cohort of 20,498 pregnant women (497 HBV carriers with 20,001 non-HBV controls) with normal alanine aminotransferase (ALT) levels was selected from the Obstetrics & Gynecology Hospital of Nantong University. The clinical parameters and PTB incidence were compared between HBV carriers and non-HBV subjects. For the meta-analysis, we searched the PubMed, Ovid and Cochrane Library databases for studies comparing PTB incidence between individuals with chronic HBV infection and non-HBV subjects. Results: HBV carriers were slightly older and had slightly higher ALT levels within normal limits. The body mass index, education and history of pregnancy between HBV carrier and non-HBV groups were comparable. PTB incidence was not associated with HBV carrier status [relative risk (RR) 0.98, 95% confidence interval (CI) 0.71-1.37] in our cohort. However, the meta-analysis involving eight published studies and our study revealed a significant association between chronic HBV infection and PTB incidence (pooled RR 1.26, 95% CI 1.19-1.33). Conclusion: While maternal HBV carriers did not have a higher incidence of PTB in our cohort, the meta-analysis indicates that individuals with chronic HBV infection appeared to be at risk of PTB as a whole.