Abstract: Objective To evaluate the efficacy of telbivudine (LdT) during the later period of pregnancy for reducing hepatitis B virus (HBV) vertical transmission from pregnant women with high viral load to their fetuses. Methods Pregnant women, with normal liver function and HBsAg-positive   and HBeAg-positive, HBV DNA ≥ 1.0 × 10 6  copies/ml were enrolled in study. They two treatment groups: LdT group (150 cases) and control group (100 cases), based upon their personal preference taking LdT or not. LdT group were adminstered 600 mg/d LdT until 6 weeks after postpartum and control group were treated without antiviral drugs. Adverse reaction was observed in LdT group after treatment, and tested the serum of HBV DNA levels at 28th week of pregnancy and the time of childbirth. Detected the serum of HBsAg and HBV of DNA of the baby within 6 hours after birth. Results HBV DNA levels in pregnant women with LdT were obviously lower than those of control group, the difference was statistically significant ( t = 5.43, P ＜ 0.001 ). There was significant difference on positive rate of serum HBV DNA of infants born within 6 hours between LdT group and control group (χ2  = 27.36, P ＜ 0.0001); HBsAg titers of control group was significantly higher than that of LdT group, with the difference statistically significant (t = 2.25, P = 0.03). No LdT discontinuations occurred due to adverse events, and no birth defects were observed in the infants delivered from LdT-treated mothers in the LdT following-up period. Conclusions LdT use during the later trimester of pregnancy in HBsAg-positive and HBeAg-positive and highly viremic mothers can safely reduce the rates perinatal HBV transmission, and significantly inhibit maternal serum HBV DNA levels in late pregnancy, and effectively block HBV intrauterine transmission with good security.