Abstract: Objective To explore the relationship between HBV intrauterine infection and delivery pattern in 1 191 neonates with HBsAg positive mothers.Methods The information on delivery pattern in HBsAg positive mothers were collected with a questionnaire survey.The hepatitis B virus(HBV)markers of the pregnant women and the neonates within 24 hours after the birth were detected with enzyme-linked immunosorbant assay(ELISA).HBV DNA contents of pregnant women and the neonates were detected with real-time fluorescent quantitative(RT)-PCR.Results There were 101 HBsAgpositive and 30 HBV DNA-positive neonates in 1 191 neonates.The rate of HBV intrauterine infection was 9.5%.There was a significant difference in the rate of intrauterine infection between the women with vaginal delivery(582)and with cesarean section(609)(χ²=18.563,P=0.001).There were significant differences in the intrauterine infection rates between viginal delivery and cesarean section for the women of HBeAg-negative and HBV DNA-negative,HBeAg-positive and HBV DNAnegative,and HBeAg-positeve and HBV DNA-positive.(χ²=7.382,4.919,5.364,P<0.05 for all).Among the HBsAg-positive women with HBV DNA level≤10³ copies/ml or 10⁵-10⁷ copies/ml,there was a correlation between delivery pattern and intrauterine infection(χ²=10.777,8.450,P<0.05 for all).Conclusion The delivery pattern has a significant effect on HBV intrauterine infection of the neonates with HBeAg positive mothers and the intrauterine infection rate could be reduced by cesarean section.