Maternal Antiviral Prophylaxis to Prevent Perinatal Transmission of Hepatitis B Virus in Thailand

Chronic hepatitis B (CHB) infection is complicated by cirrhosis and liver cancer. In Thailand, 7% of adults are chronically infected by Hepatitis B virus (HBV). The risk of perinatal transmission of HBV is about 12% when a mother has a high HBV load in her plasma, even if her infant receive specific immunoglobulin and vaccine. The hypothesis of this study is that a potent antiviral, tenofovir, can decrease HBV load in HBV infected pregnant women and therefore reduce the risk of perinatal transmission/ Pregnant women participating in this study will receive tenofovir or placebo during the last trimester of pregnancy and two months postpartum. The risk of perinatal transmission will be compared between the two groups. The results of the study will help define policy to manage HBV infected pregnant women to prevent perinatal transmission.