Maternal exposure to chemical and physical factors during pregnancy and cardiovascular malformations in the offspring.

The possible effect of chemical and physical factors during pregnancy on the occurrence of cardiovascular malformations in the offspring was studied in 573 cases and 1,055 controls. The cases represented all verified cardiovascular malformations in Finland during 1982-1984. The controls were randomly selected from all babies born during the same period. Case and control mothers were interviewed by midwives approximately 3 months after delivery using a structured questionnaire. Maternal alcohol consumption during the first trimester of pregnancy was more common among the mothers of case infants (45.9%) than those of controls (39.6%). Exposure to organic solvents at work was slightly more prevalent among the ventricular septal defect group (12.1%) than the control mothers (7.8%). However, neither association was significant when adjusted for maternal age in logistic regression analysis. Moreover, one or both of these associations may be chance effects resulting from multiple comparisons. The risk of cardiovascular malformations was not associated with maternal smoking, or coffee, tea, or cola consumption, and was equal in urban and rural areas. Maternal exposures to anesthetic gases, pesticides, wood preservatives, microwave ovens, and video display terminals at work or home were not associated with the risk of cardiovascular malformations. It is concluded that some common environmental exposures during early pregnancy to physical and chemical factors should not necessarily be considered hazardous for the developing fetal heart. The causes of the majority of cardiovascular malformations remain unknown.