Prevention of Vertical Hepatitis B Transmission by Hepatitis B Immunoglobulin in the Third Trimester of Pregnancy

Abstract

ABSTRACT

Passive-active immunoprophylaxis with hepatitis B immunoglobulin (HBIG) and hepatitis B vaccine provides a high level of protection against vertical transmission of hepatitis B virus (HBV). Nevertheless, 1 in 10 children of HBV carriers have chronic hepatitis B early in their lives despite immunoprophylaxis because they were infected in utero. This study of 469 pregnant women testing positive for hepatitis B surface antigen (HbsAg) was conducted to learn whether giving HBIG to HBV carriers in the third trimester can prevent vertical transmission of the virus. Of the women entered into the study, all of whom were asymptomatic, 126 (group 1) tested positive for hepatitis B e antigen (HbeAg), while 343 (group 2) did not. HBIG was given intramuscularly in a dose of 200 IU at 28, 32, and 36 weeks of pregnancy. All newborn infants received 100 IU of HBIG within 12 hours of birth as well as the first of 3 doses of hepatitis B vaccine (the subsequent doses were given at ages 1 and 6 months).

In group 1, 16% of infants whose mothers received HBIG in the third trimester tested positive for HbsAg at birth and 7% at age 6 months. The respective figures for infants whose mothers were not treated were significantly higher at 39% and 23%. No such treatment-related difference was observed in group 2 infants. At age 6 months, rates of protective levels of anti-Hbs antibody were 32% in group 1 infants whose mothers were HbeAg-positive and 56% in group 2 infants when the mothers had not received HBIG while pregnant. The respective figures for infants whose mothers were treated in the third trimester were 76% and 89%. Neither mothers nor their infants experienced adverse effects related to the administration of HBIG or hepatitis B vaccine.

The investigators conclude that, if all HbsAg-positive pregnant women, regardless of HbeAg status, were to receive HBIG in the last weeks of pregnancy, their infants would be better protected against chronic HBV infection.