Objectives: Birth defects are a major health burden. Primary prevention is at present emerging, i.e. folate supplementation. When it is not possible, as is still the case for most birth defects, research is needed to determine how an optimal provision of prenatal diagnosis and use of services can be achieved. Ultrasound scans in the midtrimester of pregnancy are now a routine part of antenatal care in most European countries. The objective of this study was to evaluate the prenatal diagnosis of congenital anomalies by fetal ultrasonographic examination across Europe. Methods: Data from 20 registries of congenital malformations in 12 European countries were included. The prenatal ultrasound screening programs in the countries ranged from no routine screening to 3 fetal scans offered, including 2 for biometric purposes and 1 for search of congenital anomalies, the anomaly scan. Results: There were 8,126 cases with congenital anomalies with an overall prenatal detection rate of 44.3%. Termination of pregnancy was performed in 1,657 cases (21.8%). There was significant variation in the prenatal detection rate between regions with the lowest detection rate in registries of countries without routine fetal screening (Denmark and The Netherlands) and the highest detection rate in registries of countries with at least 1 anomaly scan (France, Germany, Italy, Spain, UK). However, there were large variations among the registries with a high detection rate. There were significant differences in the prenatal detection rate and proportion of induced abortions between isolated anomalies and associated anomalies (chromosomal aberrations, recognized syndromes, and multiple without chromosomal aberrations or recognized syndromes). Conclusions: Prenatal detection rate of congenital anomalies by fetal scan varies significantly between registries of European countries even with the same screening policy. Prenatal detection of congenital anomalies is significantly higher when associated malformations are present. The rate of induced abortions varies between registries of countries even with the same detection rate of congenital anomalies. The variation described may be due to cultural and policy differences. Copyright 2002 S. Karger AG, Basel