The Liverpool Congenital Malformations Registry.

Data collection and validation for the Liverpool Congenital Malformations Registry (LCMR) are described. Founded in 1960, the LCMR increased its area of surveillance in 1979 to include five health districts in Liverpool and its environs with approximately 20,000 births per annum. The LCMR is now one of the members of the European Congenital Anomalies Register (EUROCAT). Multiple sources of ascertainment are employed, the most useful of these being OPCS notifications, hospital discharge letters and data from specialised paediatric units. In spite of several difficulties encountered in data collection the data base is an invaluable tool both for routine monitoring of prevalence rates and as a starting point for epidemiological research.