Risk factors for cardiovascular malformations in Finland.

The possible effects of genetic and environmental risk factors during pregnancy on the occurrence of cardiovascular malformations in the offspring was studied in 408 cases and 756 controls. The cases represented all registered cardiovascular malformations reported in Finland during 1982-1983. The controls were randomly selected from all babies born during the same period. Both the case and control mothers were interviewed by midwives approximately three months after delivery using a structured questionnaire. The parents of cases had more cardiovascular malformations than parents of the controls. Maternal alcohol consumption seemed to double the risk of atrial septal defect (OR = 1.9, CI95 1.0-3.4). Maternal exposure to dyes, lacquers or paints was a significant risk factor for conal septal defects (OR = 2.9, CI95 = 1.2-7.5). Maternal upper respiratory infection was twice as common among the hypoplastic left ventricle group as among the controls. Maternal smoking, coffee, tea and cola consumption and intake of acetylsalicylic acid were equally prevalent in both groups. Maternal exposure to anesthetic gases, wood preservatives or pesticides was not associated with the risk of cardiovascular malformations. The study confirms that very little is known of the etiology of congenital heart disease.