Objective To study the interruptive effect of hepatitis B virus (HBV) specific immunolobulin (HBIG) before delivery in attempt to prevent intrauterine transmission of HBV.Methods Nine hundred and eighty HBsAg carrier pregnant women were randomly divided into HBIG group and control group. Each subject in the HBIG group received 200 IU or 400 IU of HBIG intramuscularly at 3, 2 and 1 month before delivery. The subjects in the control group did not receive any specific treatment. All newborn infants received 100 IU of HBIG intramascularly after venous blood samples were taken at birth and 2 weeks after birth, followed by 30 μg plasma-derived HB vaccine or 5 μg recombinant yeast-derived hepatitis B vaccine at 1, 2 and 7 months of age. Blood tests were performed for all the lying-in women and their neonates. Blood specimens were tested for HBsAg and HBeAg by enzyme immunoassay. All infants were followed up for 1 year.Results In the HBIG group, 491 neonates were born to 487 HBV carrier mothers; and in the control group, 496 neonates were born to 493 HBV carrier mothers. The rates of intrauterine transmission in the two groups were 14.3% and 5.7% respectively (χ2=20.280, P<0.001), and the rates of chronic hepatitis B in the two groups were 2.2% and 7.3% respectively (χ2=13.696, P<0.001). The high risk factors of intrauterine HBV infection included HBsAg HBeAg double positive and HBV DNA positive in the peripheral blood of pregnant women.Conclusion HBV infection in the uterus may be interrupted by injecting multiple intramuscular HBIG injections before delivery without causing any side-effects. Objective To study the interruptive effect of hepatitis B virus (HBV) specific immunolobulin (HBIG) before delivery in attempt to prevent intrauterine transmission of HBV. Methods Nine hundred and eighty HBsAg carrier pregnant women were randomly divided into HBIG group and control group. Each subject in the HBIG group received 200 IU or 400 IU of HBIG intramuscularly at 3, 2 and 1 month before delivery. The subjects in the control group did not receive any specific treatment. All newborn infants received 100 IU of HBIG intramascularly after venous blood samples were taken at birth and 2 weeks after birth, followed by 30 μg plasma-derived HB vaccine or 5 μg recombinant yeast-derived hepatitis B vaccine at 1, 2 and 7 months of age. Blood tests were performed for all the lying-in women and Their neonates. Blood specimens were tested for HBsAg and HBeAg by enzyme immunoassay. All infants were followed up for 1 year. Results In the HBIG group, 491 neonates were born to 487 HBV c The rates of intrauterine transmission in the two groups were 14.3% and 5.7% respectively (χ2 = 20.280, P <0.001), and the rates of chronic The high risk factors of intrauterine HBV infection included HBsAg HBeAg double positive and HBV DNA positive in the peripheral blood of pregnant women. Conclusions HBV DNA was detected in 2.2% and 7.3% respectively (χ2 = 13.696, P <0.001) infection in the uterus may be interrupted by injecting multiple intramuscular HBIG injections before delivery without causing any side-effects.