LAUSR

Objectives This study aims to explore whether maternal hepatitis B carrier status is associated with an increased risk of congenital abnormalities. Design A systematic review and meta-analysis of observational studies. Data sources PubMed, Embase (Ovid), Scopus, the China National Knowledge Infrastructure (CNKI) and the Wanfang databases. Study selection Five databases were searched systematically from inception to 7 September 2021. Cohort and case–control studies that investigated the association between maternal hepatitis B virus (HBV) infection and congenital abnormalities were included. This study was conducted according to MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. Data extraction and synthesis Two reviewers independently collected data, as well as assessed risk of bias by using Newcastle–Ottawa Scale. We pooled crude relative risk (cRR) and adjusted OR (aOR) by DerSimonian-Laird random-effects model. Heterogeneity was explored by I2 statistics, Cochran’s Q test. Several subgroup analyses and sensitivity analyses were performed. Results In total, 14 studies involving 16 205 pregnant women exposed to HBV were included. The pooled cRR of 1.15 (95% CI: 0.92 to 1.45; 14 studies included) showed a marginal but not significant association between maternal HBV-carrier status and congenital abnormalities. However, the pooled aOR of 1.40 (95% CI: 1.01 to 1.93; 8 studies included) indicated that pregnant women with HBV infection might be associated with a higher risk of congenital abnormalities. Subgroup analyses of adjusted data showed a higher pooling cRR or aOR on high prevalence HBV infection populations, as well as studies from Asia and Oceania. Conclusions Maternal hepatitis B carrier status might be at potential risk for congenital abnormalities. The existing evidence was not sufficient to draw a firm conclusion. Additional studies may be warranted to confirm the association. PROSPERO registration number CRD42020205459.