[Frequency of birth defects in newborns in four regions of Poland].

Records of births from registry offices in seven provinces (Wałbrzych, Piotrków Trybunalski, Suwałki, Krosno, Rzeszów, Przemyśl, Tarnobrzeg) making four regions (south-western, central, north-eastern and south-eastern) were used for the analysis of the geographical distribution of congenital malformations. This area is inhabited by approximately 10% of the whole population with annual number of briths equal to 9% of the total number in Poland. The incidence of congenital malformations was analysed in 21.167 newborns taking into consideration such variables as smoking and other habits and occupational of parents, maternal age, and environmental pollution. In the cohort under study the incidence of malformations was different and it was as follows: Wałbrzych-1.92%, Rzeszów-1.42%, Tarnobrzeg-1.37%, Suwałki-1.23%, Krosno-1.16%, Piotrków Trybunalski-1.12% and Przemyśl-0.7%. The incidence of birth defects in infants born to young mothers (< 20 years) was 1.8% and to older ones (> 35) 1.9%. A comprehensive analysis of the environmental pollution revealed its highest level in the south-western region (the Wałbrzych province) in comparison with other study areas.