Twenty-one years of monitoring congenital malformations (1974–1994): The Israel Birth Defects Monitoring System,affiliated with the International Clearinghouse

The first 21 years of monitoring of congenital malformations by a hospital-based program affiliated to the International Clearinghouse is analyzed. The foundation activities, methodology, data and time trends are presented and precautions in interpretation of this information are emphasized. The great majority of congenital malformations, including Down syndrome, have stable rates making the search of their causes and the development of intervention methods much harder. The practical implications of these data and the appropriate recommendations are discussed.