Emtricitabine for Prevention of Vertical Transmission of HBV in Chinese Pregnant HBsAg Positive Patients

Inclusion Criteria: * HBsAg positive for more than 6 months * HBeAg positive patients: HBV DNA ≥ 5log10 copies/ml * HBeAg postive patients: ALT≥2×ULN;or liver biopsy G≥2;or liver biopsy S ≥2;or liver biopsy Knodell HAI ≥ 4 * HBeAg negative patients: HBV DNA ≥ 4log10 copies/ml * HBeAg postive patients: ALT≥2×ULN;or liver biopsy G≥2;or liver biopsy S ≥2;or liver biopsy Knodell HAI ≥ 4 * Nucleoside/nucleotide naive paitents * Diagnosed as ≥ 28 weeks pregnancy Exclusion Criteria: * Diagnosed HCC with AFP and ultrasound, CT or MRI * Creatine \>130μmol/L or Ccr \< 70mL/min * Hemoglobin \<100g/L * Coinfected with HAV,HEV,HCV,HDV or HIV * ANA \> 1:100 * Uncontrolled cardiovascluar diseases, kidney diseases,lung diseases, neurological diseases, digestive diseases,metabolic disorders, immune-compromised diseases or cancer * Drug abuse or alcohal addiction * Previous history of taking agents of lamivudine, adefovir, tenofovir entecavir or telbivudine * Long-term use of immunosuppressor or immunomodulator 6 months before enrollment to this trial * Underwent liver transplantation or liver transplantation in schedule * Allergic to nucleoside or nucleotide analogues * family history of genetic defects disease * Abnormal results in fatal defects screening * HBsAg positive sperm provider pregnancy