Racial and temporal variations in the prevalence of heart defects

Background. Documenting the prevalence and trends of congenital heart defec ts provides useful data for pediatric practice, health-care planning, and c ausal research. Yet, most population-based studies use data from the 1970s and 1980s. We sought to extend into more recent years the study of temporal and racial variations of heart defects occurrence in a well-defined popula tion. Methods. We used data from the Metropolitan Atlanta Congenital Defects Prog ram, a population-based registry with active case ascertainment from multip le sources. Heart defects were identified among liveborn infants up to 1 ye ar old, among stillborn infants, and among pregnancy terminations to mother s residing in metropolitan Atlanta. Results. From 1968 through 1997, the registry ascertained 5813 major congen ital heart defects among 937 195 infants, for a prevalence of 6.2 per 1000. The prevalence increased to 9.0 per 1000 births in 1995 through 1997. The prevalence of ventricular septal defects, tetralogy of Fallot, atrioventric ular septal defects, and pulmonary stenosis increased, whereas that of tran sposition of the great arteries decreased. For some defects, prevalence and trends varied by race. Conclusions. The prevalence of congenital heart defects is increasing. Wher eas most findings likely result from improved case ascertainment and report ing, others might be because of changes in the distribution of risk factors in the population. The basis of the racial variations is incompletely unde rstood.