[Study on the HBV intrauterine infection and its rate].
In thirty-five fetuses induced from HBsAg-positive pregnant women, the fetuses were examined for HBV markers. Another 10 fetuses were used as control and none of the fetuses was infected by HBV in utero. Among 35 fetal serum samples, HBsAg and anti-HBcIgM were detected in 4 and 5 fetuses (in 7 fetuses) respectively. One out of 17 fetal liver sections was HBcAg positive by ABC stain. Twelve out of 27 fetal livers were HBV-DNA positive. Thus, the rate of intrauterine infection of HBV was 20.0% (7/35), 5.9% (1/17) and 44.4% (12/27) respectively, by serological test, immunohistochemical test and molecular hybridization using P-labeled HBV DNA as a probe. The results showed that HBV intrauterine infection was an important mode of HBV transmission.