Approaches used for the detection of infectious agents as human teratogens.

A review of the events which lead up to the recognition of six infectious agents as teratogens showed that in most cases the associations were made through studies of the pathology of the disease or in association with epidemics which affected large numbers of pregnant women. Epidemiological studies of various populations were then conducted to obtain more complete information about the frequency of infection; the syndrome produced in the child; the effect of time of maternal infection; the method of transmission of infection; and approaches to diagnosis, treatment, and prevention of the disease. Investigation of other possible teratogens should emphasize examination of the pathology of the disease and the analysis of pregnancy outcomes of large numbers of women who experience a given infection.