Abstract: Objective To assess the efficacy and safety of telbivudine in preventing mother-to-infant transmission of hepatitis B virus （HBV） in pregnant women with high HBV DNA load.Methods This study was a randomized controlled trial and eighty pregnant women with high serum load of HBV DNA were randomly divided into the intervention group and the control group，with 40 in each group. Patients in the intervention group received telbivudine 600 mg orally once daily at the 12th week of gestation until 12 weeks after delivery. In the same time，they were also administered with compound glycyrrhizin for liver protection. The patients in the control group only received compound glycyrrhizin. All infants in both groups were vaccinated with hepatitis B immunoglobulin （200 IU） and hepatitis B vaccine （20 μg） immediately after birth. The serum HBV DNA levels in pregnant women in both groups at and 12 weeks after delivery were assayed，and the positive rates of HBsAg and HBV DNA in infants in both groups at birth and 6 months after birth were also determined. In addition，the gestation weeks，length，head circumference，weight，and Apgar scores of all infants were also recorded. Meanwhile，adverse reaction in pregnant women in two groups during the period of taking medicine was observed closely.Results At delivery and 12 weeks after delivery，serum HBV DNA levels were（3.58±0.56） lg copies/ml and （2.98±0.32） lg copies/ml in the intervention group，significant lower than those in the control group[（7.93±0.47） lg copies/ml and（7.46±0.43） lg copies/ml，respectively，P<0.01]；At birth，the positive rates of serum HBsAg and HBV DNA in infants were 5.0% and 2.5% in the intervention group，significant lower than those in the control group[20.0%and 17.5，P<0.05]；In addition，no significant differences were found in neonates between the two groups at birth as respect to gestational age （P=0.64），height（P=0.44），head circumference（P=0.93），body weight（P=0.46） and Apgar scores（P=0.45）.Conclusion Telbivudine can significantly decrease HBV DNA levels in pregnant women with high HBV DNA load，and reduce the infectious rates of HBV infection for newborns without adverse events.

Key words: Hepatitis B, Telbivudine, Mother-to-infant transmission, Safety