Frequent reproductive casualties (spontaneous abortions, stillbirths, prematurity and low birth weight, congenital malformations) were recorded in a group of 264 women who had viral hepatitis (VH) during pregnancy. The proportion of such events was much higher in the HBsAg-positive women (80%) than in the seronegative ones (44%) and it varied according to the trimester when VH had occurred. Liver disease could be incriminated as the main cause of infant death in 20 out of 2110 cases investigated; 6 of the 20 mothers proved to be HBsAg-positive. Asymptomatic HBsAg carriage in a group of 3800 pregnant women was found to be of about 8%; the prevalence of HBsAg was higher in the subgroups of women with an unfavourable pregnancy evolution.