Effect of antiviral therapy in reducing perinatal transmission of hepatitis B virus and maternal outcomes after discontinuing them

Background/Aims: There have been numerous efforts to reduce mother-to-child transmission (MTCT) of hepatitis B virus (HBV) with antiviral agents during pregnancy. However, there are limited data regarding the outcomes of pregnant women after delivery. This study was performed to evaluate the efficacy of antiviral agents in preventing MTCT of HBV and maternal long-term outcomes. Methods: The HBV-infected pregnant women treated with antiviral agents to prevent MTCT were retrospectively reviewed. Forty-one pregnant women who received telbivudine or tenofovir during late pregnancy (28-34 week) were analyzed. Hepatitis B virus surface antibody (HBsAb) positivity was tested in 43 infants after 7 months of birth. Eleven mothers were followed >1 year after delivery. Results: The mean HBV DNA titer before antiviral therapy was 8.67 (6.60-9.49) log copies/mL, and the median age at delivery was 32 years (range, 22-40). Eleven patients were treated with tenofovir and 30 with telbivudine. The median duration was 57 days (range, 23-100), and the median HBV DNA titer at birth was 5.06 log copies/mL (range, 2.06-6.50). Antiviral treatments were associated with significant HBV DNA reduction (P<0.001). Among 43 infants (two cases of twins), HBsAb was not detected in two, subsequently confirmed to have HBV infection. Biochemical flare was observed in two of 11 mothers followed >12 months, and an antiviral agent was administered. Conclusions: Antiviral treatment during late pregnancy effectively reduced MTCT. Long-term follow-up should be required in such cases. In addition, given that maternal biochemical flare occurred in 18% of mothers, re-administration of antiviral agents might be required.