Objective: A survey of prenatal diagnostic of inborn defects in 2002 and analysis of the share of prenatal diagnostics in the general incidence of inborn defects in the Czech Republic during 1996–2002. Design: A retrospective study. Materials and Methods: The data were obtained from the Medical genetics wards (32 workplaces) – inborn defects detected during prenatal diagnostics and data from the Institute of Medical Information and Statistics of CZ and the National Registry of Inborn Defects – inborn defects in newborns. Eight types of inborn defects (anencephaly, spina bifida, congenital hydrocephalus, omphalocele, gastroschisis, kidney agenesis/hypoplasia, kidney cystic disease and Down syndrome) were selected from the available material for detailed analysis. Results: In the period of 1996–2002, 3,621 pregnancies with inborn defects were detected and ended and 1,351 fetuses were diagnosed prenatally, but the pregnancy was not ended. The prenatal detection of inborn defects has been gradually increasing. A detailed analysis of prenatal diagnostics in 2002 has shown that inborn chromosomal aberrations were diagnosed most frequently (307 times), most frequent of them being obviously Down’s syndrome (108 times). The other inborn defected were those of urinary tract (agenesis/hypoplasia of the kidney 13 times, cystosis of the kidneys 25 times, hydronephrosis 31 times, other inborn defects 10 times), inborn heart defects, defects of neural tube (anencephaly 18 times, encephalocele 6 times, spina bifida 22 times), inborn defects of skeletal and muscular system (46 times), defects of abdominal wall (omphalocele 10 times, gastroschisis 25 times). A detailed analysis of selected eight types of inborn defects indicates that the prenatal detection of inborn defects has been on the increase and prenatal diagnostics significantly participated in the general detection rate of inborn defects. The percentage of prematurely ended pregnancies from the total number of diagnosed defects has been close to 100% in anencephaly, 50-60% in spina bifida, 50–60% in omphalocele as well, 70–90% in gastroschisis, 20–30% in agenesis/ hypoplasia of the kidneys and 60–70% in Down’s syndrome. Conclusion: In the observed period of time there have been increasing numbers of prenatally diagnosed inborn defects. There is a difference between the cases diagnosed prenatally in general and the number of those diagnosed prenatally and ended prematurely. There is an increasing number of cases which are not ended (the decision of the pregnant woman, multiple pregnancies, late detection of the inborn defect). The efficiency of prenatal diagnostics in the observed period has been between 50 and 100% in relation to the type and severity of the inborn defect.

        Key words: prenatal diagnostics, inborn defect, anencephaly, spina bifida, congenital hydrocephalus, omphalocele, gastroschisis, agenesis/hypoplasia of the kidneys, cystic kidney disease, Down’s syndrome.