Risk of hepatitis B transmission after amniocentesis in chronic hepatitis B carriers.

OBJECTIVE: To measure the risk of perinatal transmission of HBV in chronic carriers who undergo amniocentesis. METHODS: This was a prospective, longitudinal study from 1990 to 1995 of women who were HBV carriers and underwent amniocentesis. The infants of these women were followed from birth to one year of age. Maternal data examined included HBV antigen and antibody status, liver function tests (LFTs) and the amniocentesis report. RESULTS: Twenty-eight women were identified. Two of 28 neonates were stillborn unrelated to hepatitis. Five infants were lost to follow-up leaving 21 mother-child pairs to evaluate. All 21 women were chronic HBV carriers at the time of amniocentesis for delivery. No mother had abnormal LFTs, and only one of 21 women was positive for hepatitis B e antigen (HBeAg). Thirteen amniocenteses were for advanced maternal age, and four were for abnormal maternal serum alphafetoprotein (MSAFP) screening. None of the amniocenteses were recorded as bloody, and the placenta was anterior in 6 of 21 procedures. None of the 21 infants (95% CI: 0-16.8%) were positive for HbsAg during the first month of life or at 12 months of age. All infants received HBV vaccine and HBIG immunoprophylaxis. CONCLUSION: The risk of transmission of HBV to the fetus after amniocentesis in women who are HBV carriers is low. Immunoprophylaxis in these infants was successful.