Objective       To determine the change of transmission of HBsAg

HBeAg and anti-HBC through placenta in HBV infected pregnant women at the second and third trimesters after the treatment of telbivudinein.       Methods      We systematically investigated 69 mothers with HBeAg positive and HBV DNA levels ≥10

6

IU/mL who made routine pregnancy checks in our hospital from Feburary 2008 to October 2012 and receive

d telbivudine at 600 mg per day from 24th to 33th week of gestation. Another 15 pregnant women at the same situation who were unwilling to receive the treatment served as control. All the mothers and the cordblood of infants were detected for the serum HBV markers (HBsAg

anti-HBs

HBeAg

anti-HBe

HBV DNA).       Results       There was no significant difference in serum levels of HBsAg

HBeAg and anti-HBC titers in the mothers and their infants from either the telbivudine group or the untreated group (serum of mothers at delivery

HBsAg P=0.058

HBeAg P=0.065;  blood of infants

HBsAg P=0.761

HBeAg P=0.225). There was alson no difference of the transmission rate of HBsAg and HBeAg between two groups (P=0.172 and P=0.163). The sesum anti-HBc could absolutely transit the placenta in the two groups.       Conclusions      We demonstrated that telbivudine couldn’t effectivly downregrade the levels of serum HBsAg and HBeAg of the mothers and the transmission rate of cordblood in the telbivudine group. The mechanism of telbivudine preventing mother to infant transmission might be due to its declining the levels of HBV DNA. The levels of serum HBsAg and HBeAg in the mother is not parallel to the transmission rate of cordblood and the mothers.