Acquisition of hepatitis B antigen in the newborn period.

This paper describes six mother and infant pairs where the mother developed serum hepatitis during pregnancy. These findings are compared with those in three Australian antigen carrier mothers and their babies. The literature is also reviewed and it is concluded that neonatal hepatitis seldom occurs in infants whose mothers have hepatitis early in pregnancy or are chronic carriers of Australia antigen. In contrast the risk of infection of infants born to mothers who develop serum hepatitis later in pregnancy or in the puerperium approaches 50%.