Temporal variability in birth prevalence of congenital heart defects as recorded by a general birth defects registry.

Objective: Our aim was to examine the temporal variability in congenital heart defect (CHD) birth prevalence from 1980 to 2000 in Emilia-Romagna, Italy.

Methods: The study population consisted of all infants, surveyed by the Emilia-Romagna birth defects registry (Indagine Malformazioni conpenite in Emilia-Romagna [IMER]), who were affected by CHDs. A simplified classification into "simple" and "complex " CHD was adopted. A comparison with another epidemiologic study using different methodology in the same area was performed.

Results: From 1980 to 2000, IMER ascertained 2442 live births with CHD of 480,793 infants born, with an average CHD birth prevalence of 5.1% (Range, 3.1% to 7.5%). A significant increase in prevalence of simple CHD during the second decade of the study was demonstrated because of an increased recognition of "minor" cardiac lesions among the simple CHD. The birth prevalence of complex CHD remained stable.

Conclusions: The apparent increase in live births with CHD results mainly from the current widespread availability of color Doppler echocardiography, which allows the early detection of the "minor" cardiac defects. Other differences are the result of the sources of ascertainment, diagnostic criteria, system of classification, and especially the age limit for enrolling infants with suspected CHD.