Methods Sera sample of HBsAg positive pregnant women and their newborns were collected in Tai Yuan infectious disease hospital from Nov 2001 to Jul 2004.Samples with HBV DNA positive were tested by nPCR and sequencing.

• 方法收集2001年11月至2004年7月在太原市传染病医院妇产科住院的HBsAg阳性孕妇及其新生儿外周血,选取其中部分HBV DNA阳性标本进行nPCR产物直接测序,分析HBV“a”决定簇变异情况,比较HBV“a”决定簇突变组孕妇与未突变组孕妇HBV宫内感染率的差别。