Ten-year birth defect epidemiological surveillance in North-Western Croatia

This paper presents selected data of a ten-year epidemiological surveillance of birth defects in the North-Western part of the Republic of Croatia, carried out within the framework of the European population registry network. The mean prevalence of birth defects in the period from 1990 -1999 in observed regions was 17.6/1000 births, which is in consistence with the mean rate of birth defects of the EUROCAT registries. The musculoskeletal system anomalies were the most common (32.0%), followed by the heart defects (24.2%). Chromosomal aberrations (7.8%), oral clefts (7.4%) and central nervous system anomalies (6.3%) were several times less frequent. The rates of selected major malformations did not significantly differ from the data of other European centers. A high frequency of polydactyly in the region of Varaždin was noticed, compared to other Croatian regions, as well as to the mean prevalence of the EUROCAT registries, which was two times less frequent (16.9/10000 compared to 8.8/10000). The most frequent heart anomalies were ventricular and atrial septal defects. The total prevalence of trisomy 21 in Croatia did not differ from the prevalence in other European regions. A gradual reduction of the prevalence of trisomy 21 was observed, which could be attributed to a more efficient prenatal care. A lower frequency of trisomy 21 in the region of Varaždin is probably due to the higher rate of younger mothers which is characteristic of the population in this region. A gradual decrease of the neural tube defects frequency was observed as well, probably as the consequence of a more frequent periconceptional folic acid prophylaxis. A routine hospital statistics is registering only a tenth of the anomalies included in the registry, and therefore we cannot consider it a reliable indicator of the birth defects frequency in the Republic of Croatia. There is a need of organizing a population-based registry of births defects for the whole of Croatia, which should be integrated in the present European registry network.