Low risk of mother to infant transmission of hepatitis B virus in Guipúzcoa (Basque country, northern Spain).

The prevalence of HBsAg carriers in 18,196 pregnant women (64% of women who gave birth in Guipúzcoa in 1986-1991) was 0.61% (0.43% for the last two years of the study). Three of the carriers were also HBeAg/HBV-DNA positive and two were anti-HDV positive. Anti-HBc prevalence was 6.5% in 602 20-40 year old women and 1.6% in 428 girls 10-11 years old (0.47% of gypsy ethnic subjects are not included).