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.
Keywords: Antiviral agents; chronic hepatitis B; infant; pregnancy; pregnancy complications.