Molecular Epidemiological Study On The Intrauterine Transmission Of Hepatitis B Virus Through Placental Infection

Purposes Hepatitis B virus(HBV) can transmit to fetus through placenta, and result in an intrauterine infection. The intrauterine infection rate of HBsAg carring pregnant women's fetuses is about 5 to 15%. At present, there are only a few reports about the role of placenta in HBV intrauterine transmission at home and abroad, and the results and conclusions are contradictory. Those studies did not clearly reveal the mechanisms, transplacental route and the timing of intrauterine infection. So it's difficult to make an effective approach to prevent HBV infection in utero. In this study, we will probe into (1) HBV infection status of placenta; (2) the relationship between placental infection and intrauterine infection; (3) the risk factors of placental infection and intrauterine infection; (4) the route of transplacental transmission; (5) the timing of intrauterine infection; and (6) the direction of further study and possible preventive measures.Methods We collected 101 term placentas and sera from mothers and their newborn infants, 24 aborted first-trimester placentas and sera from those pregnant women, and 11 induced aborted second-trimester placentas and sera from HBsAg carrying pregnant women. Serologic HBV markers (HBsAg, anti-HBs, HBeAg, anti-HBe, anti-HBc and HBV DNA) of pregnant women and newborns were determined by ELISA or PCR. Maternal serum HBV DNA level was quantitated by molecular hybridization techniques. The HBsAg, HBxAg, HBcAg and HBV DNA in placentas were detected by ABC immuno-histo-chemical staining or in situ hybridization. The epidemiological data were...