Pregnancy outcomes for pregnant women with chronic hepatitis B exposing to entecavir or adefovir dipivoxil therapy before or in early pregnancy

Abstract Background Entecavir (ETV) or adefovir dipivoxil (ADV) are not recommended during pregnancy because of embryotoxicity or teratogenicity found in animal studies; however, information on the safety of ETV or ADV in humans is limited. Aims The aim of this study was to investigate the safety of ETV or ADV in women with chronic hepatitis B (CHB). Methods We retrospectively enrolled 152 pregnant women with CHB who exposed to ETV or ADV in the first trimester of pregnancy. All the mothers were followed until postpartum 7 months. All newborns received immunoprophylaxis. The primary endpoint was the safety of mothers and infants. The secondary endpoint was the rate of mother-to-child transmission (MTCT) of hepatitis B virus (HBV). Results The pregnant women were divided into two groups. Group 1 included 20 pregnant women who became unplanned pregnancy with ETV or ADV treatment. All of them switched to TDF before 7 weeks of gestation. There were 20 women with 20 pregnancies and 18 live births. Group 2 included 132 with TDF before conception. There were 132 women with 141 pregnancies and 125 live births. The abortion rate of Group 1 was not higher than that in Group 2 (10.0 versus 10.6%, p = 1.000). The birth defect rate in Group 1 did not statistically differ from Group 2 (5.6 versus 4.8%, p = 1.000). There were no significant differences of gestational complications between the two groups. The rate of MTCT of HBV is 0%. Conclusions Among infants exposed to ETV or ADV before conception, ETV or ADV was not associated with a higher risk for adverse birth outcomes.