Mother-to-Child-Transmission (MTCT) of HBV is the most important route in high endemic countries. Although active-passive immune prophylaxis is generally administrated to infants delivered by HBsAg positive women, there are a lot of people infected with HBV in China. High HBV DNA load (>10^5IU/ml) is the vital cause of MTCT. So some researchers used TDF （tenofovir） or LDT（telbivudine） to treat patients with high HBV DNA load during middle, late pregnancy, in order to decrease MTCT. As a result, some data about it were gradually reported in late years. Recently, American Association for the Study of Liver Diseases, European Association for the Study of Liver Diseases and China guidelines for CHB (chronic hepatitis B) suggest that pregnant women with high HBV DNA load be treated with TDF or LDT at 24-28 weeks of gestation to lower MTCT of HBV.