Regional differences in the prevalence of congenital heart defects

Prevalence of congenital heart diseases was studied prospectively in all 664,218 infants live born in Bohemia from 1977 to 1984. All children who died were autopsied and those suspected of having a heart disease were examined at the specialized center. In total, 664/100,000 infants were born with a heart defect, most of them in Prague (957,9/100,000) and in Central Bohemia (739.4) and in Northern Bohemia (619.3). The lowest prevalence was found in West Bohemia (515.1/100000 live births). The relative frequency of congenital heart defect categories differed significantly among regions. Evidence of regional differences in prevalence of congenital heart diseases and their forms suggests that environmental factors can play an important role in the etiology of congenital heart defects.