Abstract: Objective To study the virologic determinants of spontaneous seroclearance or seroconversion of HBeAg and/or HBsAg in pregnant women who are chronic hepatitis B virus （HBV） carriers. Methods The pregnant women diagnosed as chronic HBV carriers between August,2002 and July,2004 were included and followed up between October,2009 and March,2010. The HBV serologic markers and HBV DNA were detected. Results A total of 419 individuals were recruited in this study,and the average follow-up period was 6.4 years. Although 155 women lost,a total of 264（63.0%） women were successfully followed up,of whom 76 （28.8%） were HBeAg-positive at presentation. 55.3% （42/76） of HBeAg-positive women were seroconverted to anti-HBe spontaneously at the follow-up. Compared with 34 women without seroconversion,42 with HBeAg/anti-HBe seroconversion had lower levels of serum HBV DNA,HBeAg and HBsAg（all P<0.01）. The postpartum HBeAg seroconversion rate in 6 pregnant women with HBV DNA <1×10⁶ IU/ml,17 with HBeAg <700 S/CO,and 13 with HBsAg<1×10⁴ IU/ml were 100.0%,100.0% and 92.3%,respectively. The spontaneous HBsAg seroclearance was found in 38 （14.4%） women at the follow-up. The serum HBsAg levels at presentation were significantly lower in women with HBsAg seroclearance than 226 without HBsAg seroclearance （P<0.001）. The postpartum HBsAg seroclearance rate in 25 pregnant women with HBsAg <100 IU/ml was as high as 56.0%. Conclusions HBeAg-positive women with serum HBV DNA <1×10⁶ IU/ml,HBeAg <700 S/CO and/or HBsAg <1×10⁴ IU/ml are more likely to undergo spontaneous HBeAg seroconversion,and those with serum HBsAg <100 IU/ml have a higher chance of spontaneous HBsAg seroclearance.

Key words: Hepatitis B virus carrier, Pregnant women, HBeAg seroconversion, HBsAg seroclearance