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.