Hepatitis B virus (HBV) infection is of high prevalence in China. Mother-to-infant transmission is the major route for HBV transmission and subsequent chronicity. This study aimed to investigate current HBsAg-positive rate among pregnant women and immunoprophylaxis outcome in China. Multicenter prospective study was conducted in 10 centers. From 2008 to 2012, 67,720 pregnant women were screened and 1,150 HBsAg-carrier mothers and their infants aged 8-12 months were studied in four out of all centers, among whom HBV markers (HBsAg, HBsAb, HBeAg, HBeAb, and HBcAb) and HBV DNA (in three centers) were measured. The results showed that HBsAg-positive rate of pregnant women was 6.7 % (4,533/67,720) and infants' immunoprophylaxis failure rate was 3.4 % (39/1,150). Immunoprophylaxis failure infants were all born to mothers of HBeAg-positive and HBV DNA ≥6 log10 copies/ml. Among infants of HBeAg-positive mothers, multivariable analyses showed the following: mother's age <28 years vs ≥28 years, RR = 0.157, 95 % confidence interval (CI) [0.067, 0.369], p = 0.000; Neonates receiving vaccine vs vaccine plus hepatitis B immune globulin (HBIG), RR = 0.371, 95 % CI [0.167, 0.825], p = 0.015. Pregnant women receiving HBIG in the third trimester, vaginal delivery and breastfeeding had no significant effects on HBV mother-to-infant transmission.
Conclusions: Pregnant women are still of high HBsAg prevalence in China. HBV mother-to-infant transmission still occurs after passive-active immunization. Pregnant women of high HBV replication levels are the major risk population of HBV mother-to-infant transmission. Passive-active immunization is necessary for neonates of HBeAg-positive mothers. Mother's age <28 years and neonate receiving vaccine only were the risk factors for HBV mother-to-infant transmission. Breastfeeding did not put children at risk of mother-to-infant transmission.