Paper 1: The EUROCAT network--organization and processes.

The European Surveillance of Congenital Anomalies (EUROCAT) is a network of population-based congenital anomaly registries in Europe, funded by the European Union, which has been in operation for more than 30 years. It currently surveys more than 1.7 million births per year, including 31% of births in the European Union, and includes almost all population-based European congenital anomaly registries as its members. EUROCAT member registries collect data, ascertained from multiple sources, on all major structural congenital and chromosomal anomalies. EUROCAT surveillance relates to three areas: prevalence, primary prevention, and prenatal screening. This article describes the history of EUROCAT and gives an overview of the current methodology and work of EUROCAT covering the database content and management, coding and classification of anomalies, core surveillance, prevalence tables, statistical monitoring. The monitoring of new developments in prenatal diagnosis, medication during pregnancy, use of folic acid, and investigation of clusters and exposures are overseen by working groups responsible for organizing research and producing regular reports. The EUROCAT Web site includes current data on prevalence rates and prenatal detection rates-an example of information useful to clinicians, public health service managers, and patients.