Incidence and Risk Factors of Intrauterine Transmission Among Pregnant Women With Chronic Hepatitis B Virus Infection

Goals: To identify the potential risk factors of hepatitis B virus (HBV) intrauterine transmission and predict the incidence of HBV intrauterine transmission among hepatitis B surface antigen–positive pregnant women with diverse viral load. Background: The intrauterine transmission of HBV significantly contributes to the persistence of a high number of patients infected with HBV. However, its risk factors remain unclear. Materials and Methods: A prospective study was performed on hepatitis B surface antigen–positive pregnant women who delivered from June 2012 to December 2016 at Wuhan Medical Care Center for Women and Children, Wuhan, China. Results: In total, 1200 women paired with 1219 infants were enrolled. In total, 11 (0.9%) infants were identified with intrauterine transmission. We observed that all infants with intrauterine transmission were born to hepatitis B e antigen–positive mothers who had serum HBV DNA levels >7 log10 copies/mL. Our study suggested that the HBV DNA levels (for each log10 copies/mL increase, odds ratio=5.43; 95% confidence interval, 1.31-22.43; P=0.019) had independent effects on HBV intrauterine transmission in a multivariate logistic regression model. Moreover, cesarean section (odds ratio=0.18; 95% confidence interval, 0.04-0.74; P=0.018) was associated with a reduced risk of HBV intrauterine transmission. The predictive rates of intrauterine transmission were 0.06%, 0.50%, 2.81%, 8.89% in infants with maternal HBV DNA levels of 105, 106, 107, 108 copies/mL, respectively. Conclusions: Our data confirmed that increasing maternal viral load has the ability to predict intrauterine HBV transmission. Vaginal delivery increased risk of HBV transmission in infants compared with cesarean section. Further studies are warranted to clarify the possible mechanism underlying these associations.