Abstract
One-hundred and four infants with congenital heart disease were identified from their birth certificates and matched with normal controls. Their gestational histories were examined to see whether they had been exposed to exogenous sex hormones. Exposure was 8-5 times more common among the infants with malformations than among controls. A history of hormone exposure was more common among those patients with multiple malformations, and the exposed infants were also more likely to have died (and to have died earlier) than those who had not been exposed, which suggests that hormone exposure causes severe types of malformations. The commonest type of exposure was to hormone pregnancy tests, which was needless exposure. Only two of the mothers of malformed infants had inadvertently used oral contraceptives in the first trimester.