Prevalence and geographic disparities in certain congenital anomalies in Quebec: comparison of estimation methods.

The purpose of this study was to estimate the prevalence of congenital anomalies in Quebec from MED-ECHO hospitalization records and from records of stillbirths. The results are first compared with those from the Canadian Congenital Anomalies Surveillance System (CCASS) for Quebec and Canada; then the data are examined by period and region of residence. The study results show that, for the congenital anomalies selected for the study, the prevalence rates measured for Quebec from the MED-ECHO data tend to be lower than the prevalence rates for Canada, whereas the rates estimated by CCASS are higher for Quebec than for Canada. The MED-ECHO data cover practically all Quebec births, compared with only 15% coverage by CCASS, and therefore provide a more accurate picture of congenital anomalies in Quebec.