The purpose of this study is to evaluate the efficacy and safety of telbivudine and lamivudine use during late pregnancy for the prevention of HBV perinatal transmission in highly viraemic mothers.

This study enrolls HBV mono-infected pregnant women cohorts managed in outpatient clinics/delivery unit at YouAn Hospital in Beijing. Subjects are prospectively followed from gestation week 26 to postpartum week 52. Treatment naïve mothers with HBV DNA > 6 log10 c/mL and normal ALT are eligible. Mothers with abnormal fetus, cirrhosis or evidence of hepatocellular carcinoma (HCC) are excluded. At gestation week 28, mothers will receive telbivudine (LdT) 600 mg per day or lamivudine (Lam) 100 mg per day until postpartum 4 or no treatment as per their preference. All infants will receive standard immunoprophylaxis. Data is collected from patient records using data extraction forms. Primary endpoints are vertical transmission rates at infants' age of 52 week and the safety of telbivudine or lamivudine use.

Inclusion Criteria:

1. Age: 20-40 years old
2. HBsAg, HBeAg positive and HBV DNA >6 log10 copies/ml
3. Gestational age: 26-28 weeks with normal fetus
4. Willing to consent for the study

Exclusion Criteria:

1. Elevated ALT
2. Antiviral treatment experience patients
3. Co-infection with HAV, HCV,HDV, HIV
4. Concurrent treatment with immune modulators, cytotoxic drugs, or steroids
5. Clinical signs of threatened miscarriage in early pregnancy
6. Clinical evidence of cirrhosis and/or hepatocellular carcinoma