OBJECTIVETo study the effect of different delivery modes on immunoprophylaxis efficacy so as to clarify whether or not cesarean section reduces immunoprophylaxis failure.

METHODSMothers with positive hepatitis B surface antigen (HBsAg) were selected in the third trimester of pregnancy. Their babies were inoculated with hepatitis B immunoglobulin at birth and hepatitis B vaccine at 1, 2 and 7 months of age. HBsAg and its antibodies (anti-HBs) were tested at 1, 4, 7, and 12 months of age, then followed up yearly.

RESULTSA total of 301 babies entered the study, including 144 born by normal spontaneous vaginal delivery, 40 by obstetric forceps or vacuum extraction, and 117 by cesarean section. The incidence of mother's HBeAg positivity or baby's gender constitution was comparable between the three groups. There were no significant differences in the positive rate of anti-HBs or HBsAg at follow-up periods among the three groups. At 12 months of age, anti-HBs could be detected in 78.9% of the babies born by normal vaginal delivery, 84.6% of the babies by forceps or vacuum extraction, and 86.4% of the babies by cesarean section. The positive rate of HBsAg was 8.1%, 7.7%, 9.7%, and chronic HBV infection incidence was 7.3%, 7.7%, 6.8% respectively.

CONCLUSIONSThere are no significant effects of delivery mode on the interruption of HBV maternal-baby transmission by immunoprophylaxis. Cesarean section does not reduce the incidence of immunoprophylaxis failure.