Hepatitis B (surface) antigen in mothers and their infants.

Hepatitis B (surface) antigen (HBSAg) was found in the serum of 8 out of 4 245 women attending the antenatal clinic of the Queen Victoria Maternity Hospital Seven (0, 16%) were asymptomatic carriers of the antigen, while the eigth suffered from polyarteritis nodosa. Seven of the 8 babies born to these mothers were followed-up over periods of up to 18 months, and 1 has become a chronic carrier of HBSAg. The antigen was not detected in the colostrum (breast milk) of the 6 positive mothers tested, but it was present in amniotic fluid, placenta and cord blood of some of the mother-infant couples. The possible routes of transmission of the hepatitis B virus from mother to baby are discussed in the light of these findings. No cases of acute virus B hepatitis occurred in the latter months of pregnancy nor in the puerperium, among 4 088 women delivered at the hospital during this period.