Optimal Time for Tenofovir Treatment of Anti-Hepatitis B Virus (HBV) During the Pregnancy

To determine the optimal time for the Tenofovir treatment of anti-Hepatitis B Virus (HBV) during the pregnancy among women with chronic HBV infection and high HBV DNA load. This is a randomized, open-label, three-arms, parallel-controlled clinical trial. Pregnant women with high HBV load and normal liver function will be treated with tenofovir during the middle or late stage of pregnancy, started from 24th gestational week, 28th gestational week and 32th gestational week through 1 month postpartum, respectively. The HBV DNA load at 40th gestational week of mothers, the intrauterine HBV infection rate of infants will be compared across the three groups.