Secular trend of age-specific prevalence of hepatitis B surface and e antigenemia in pregnant women in Taiwan.

To elucidate the impact of aging of hepatitis B carrier women on their viral replicative markers in a hepatitis B endemic area, all the parturients admitted to the Hospital were studied from 1985 to 2000. Serum hepatitis B surface (HBsAg) and hepatitis B e antigen (HBeAg) were tested by radioimmunoassay. Mann-Whitney U and Student's t-tests were used for statistical analysis. The results showed the yearly prevalence rate of HBsAg in pregnant women seemed stable with a mean of 12.0 +/- 1.1% during the period. The yearly positive rate of HBeAg among HBsAg-positive pregnant women varied between 30.4% and 42.6% from 1985 to 1992 and declined from 29.6% in 1993 to 18.1% in 2000. The mean ratio of HBeAg/HBsAg in carrier parturients was 24.7% [intraquantile range (IQR) 20.5-28.4] from 1993 to 2000, which was significantly lower than that of 32.4% (IQR 31.0-39.0) from 1985 to 1992 (P < 0.0001). The mean age of HBeAg-positive primiparas from 1993 to 2000 was 29.1 +/- 3.9 years and significantly higher than that of 28.0 +/- 3.7 years from 1985 to 1993 (P < 0.001), as well as in secundiparas 31.2 +/- 3.8 years vs. 30.1 +/- 3.4 years (P < 0.001) and in total parturients 30.3 +/- 4.2 years vs. 29.3 +/- 3.8 years (P < 0.001). Thus, no significant decrease of HBsAg carriage was observed in the past 16 years, whereas a decreased ratio of HBeAg/HBsAg was noted in carrier parturients in the past 8 years and the elderly HBeAg-positive parturients from 1993 to 2000 may be the cause.