Siffel_1997_Cent.Eur.J.Public.Health_5_79

The Hungarian Congenital Abnormality Registry (HCAR) was established in 1962 due to the growing public health importance of congenital abnormalities (CAs). The HCAR is a population-based registry; it collects and keeps permanent records of medical and personal information about malformed newborns and infants (notification of CAs Is mandatory for physicians) in order to develop baseline data for different types of CAs, to search for increases in the incidence of specific CAs, to provide rates, and identify geographic areas of concern for cluster investigation. In the last 25 years numerous studies have been carried out. In the 1970s two significant increases were noticed: i) in the rate of terminal transverse type of limb reduction defects and ii) in the rate of hypospadias. As a result of our epidemiological investigations and case-control studies we were able to identify the possible factors which caused these increases. In the first case, for example, the Ministry of Health changed the policy of using high oestrogens dosage (which increased the risk of this defect 6.1 times) for artificial abortions in 1978 and after this time the increase was stopped. In 1989-1990 a geographical cluster was found. An extremely high rate of cases with Down's syndrome (27%) was identified in a small village and the case-control study and environmental investigations pointed suspicion on the excessive use of a chemical, trichlorfon at local fish farms. All mothers of babies with Down's syndrome had consumed contaminated fish during critical period. The use of this chemical was prohibited and no CAs were recorded after this time at this place. A special case-control surveillance system has been operating since 1980 in Hungary based on the HCAR. The objective of this system is to obtain information on pregnancy exposures and other risk factors for the study and identification of causes of CAs. The teratogenicity of several drugs taken during pregnancy has been examined so far, most of them ended up with negative results. Our system is suitable for surveillance, research and intervention.