MATERIALS AND METHODS 2.1 Subjects, time and location of study 2.1.1 Research subjects + Selection criteria - Pregnant women with chronic HBV infection having a HBV DNA load > 10 copies / mL 7 - Children of the above-mentionned women born during the study - Voluntary to participate in the research + Exclusion criteria - Pregnant women co-infected with HIV or hepatitis C - Pregnant women have clinical manifestations and tests showing liver, kidney, blood disease, pregnancy toxicity, gestational diabetes. - Pregnant women with abnormal test: AST, ALT ≥ 2 times the upper normal limit, blood creatinine> 150 µmol / l, Haemoglobin <80 g/l.