Risk factors for hypoplastic left heart syndrome.

A case-control study was performed in Finland to investigate the etiology of the lethal heart malformation, hypoplastic left heart syndrome (HLHS). The cases represented all verified HLHS (n = 34) in Finland during 1982-1983, and controls (n = 756) were randomly selected from all babies born during the same period. Both case and control mothers were interviewed by midwives approximately 3 mo after delivery. Maternal upper respiratory infection during the first trimester of pregnancy was a significant risk factor for HLHS (OR = 2.5, Cl95 = 1.2-5.4). Maternal exposures at work to factors such as disinfectants, pesticides, dyes, lacquers or paints, and anesthetic gases were rare and failed to indicate any risk for HLHS. Maternal use of deodorants or hairsprays during the first trimester of pregnancy was not a significant risk factor for HLHS (OR = 1.8, Cl95 = 0.9-3.6). The risk of HLHS was not associated with seasonal variation, maternal smoking, alcohol or coffee consumption, or use of acetosalicylic acid. Because the study material is limited in size, the power of this investigation is weak for testing the teratogenicity of specific chemicals on the risk of HLHS. Thus, conclusions from the negative findings of this study should be drawn very carefully.