Secular trends of HBeAg prevalence among HBsAg-positive delivery mothers in a hepatitis B endemic area.

A high prevalence of HBeAg among HBsAg-positive mothers at the time of delivery results in a high prevalence of hepatitis B vertical transmission. From 1990 to 1995, 896 pregnant HBsAg-positive women, including 411 (46 per cent) HBeAg-positive subjects, were enrolled in our study to analyse the secular change in HBeAg prevalence. Their mean age, number of pregnancies and parity were 29.5 +/- 4.1 years, 2.0 +/- 1.2, and 0.6 +/- 0.7, respectively. The prevalence rates of HBeAg were 48, 54, 49, 47, 40, and 40 per cent among the subjects enrolled in 1990, 1991, 1992, 1993, 1994, and 1995, respectively. In univariate analyses, prevalence of HBeAg decreased by the calendar year of pregnancy (p = 0.01), and also by age (p < 0.00001), number of pregnancies (p < 0.0001) and parity (p < 0.0002). After adjusting for age in multiple logistic regression, the calendar year of pregnancy was still the independent variable, while gravida and parity became insignificant. The odd ratios (95 per cent confidence interval) of HBeAg negative-seroconversion in the equations were 1.09 (1.00-1.19) per calendar year and 1.14 (1.10-1.18) per year of age. Our results have shown a secular decrease in HBeAg-prevalence among pregnant HBsAg-positive women in Taiwan.