Occupational risk factors for congenital heart disease.

To investigate possible associations between cardiovascular malformations and maternal occupational exposure to various factors during the first trimester of pregnancy, 406 cases and 756 controls were studied retrospectively. The cases were taken from all infants diagnosed with cardiovascular malformations born in Finland during 1982 and 1983. The controls were randomly selected from all normal births in the country during the same period. All mothers were interviewed approximately 3 months after delivery by a midwife, using a structured questionnaire. Maternal overall exposure to chemicals at work was more prevalent among the case group (35.8%) than the control group (26.2%, P less than 0.01). Among the specific chemical groups, maternal exposure to dyes, lacquers, or paints was significantly associated with the risk of congenital heart disease. Exposure to organic solvents during the first trimester seemed to increase to risk of ventricular septal defect (P less than 0.05). Work at video display terminals was slightly more prevalent among the case group (6.3%) than among the control group (5.0%). The mothers' education level, regular exposure to passive smoking at work, or temperature at the workplace were not risk factors for congenital heart disease in the offspring, neither was maternal exposure to microwave ovens, disinfectants, pesticides, or anesthetic gases. It is concluded that many maternal exposures at work seem not to have a teratogenic effect on the fetal heart, although the limited power of this investigation needs to be borne in mind.