Objectve: An analysis of prenatal diagnostics of congenital malformations in the year 2002 and an analysis of the proportion of prenatal diagnostics in the total incidence of congenital malformations in the Czech Republic in the years 1994 – 2002. Design: A retrospective study. Setting: Department of Medical Genetics, Faculty Thomayer Hospital, Prague. Materials and Methods: The data were obtained from Dept. of Medical Genetics wards (28 departments) – congenital malformations were detected during prenatal diagnostics, and other data were obtained from the Institute of Medical Information and Statistics of the Czech Republic, the National Registry of Inborn Defects – Congenital Malformations in Newborns. From the available material the authors selected six types of congenital malformations (anencephaly, spina bifi da, omphalocoele, gastroschisis, renal agenesis/hypoplasia, Down syndrome) for a more detailed analysis. Results: In the period of 1994-2002 a total of 3,621 pregnancies with congenital malformations were detected and terminated and 1,351 fetuses were prenatally diagnosed, but the pregnancy was not terminated. The prenatal detection of inborn errors is gradually increasing. A detailed analysis of prenatal diagnostics in 2002 indicated that chromosomal aberrations were diagnosed most frequently (307 cases), of which Down syndrome was most frequent (108 cases). The next most frequent defects were those of urinary tract (agenesis or renal hypoplasia 13 times, kidney cystosis 25 times, hydronephrosis 31 times, other congenital malformations 10 times), congenital heart malformations (dealt with in another presentation), defects of neural tube (anencephaly 18 times, encephalocoele 6 times, spina bifi da 22 times), congenital malformations of skeletal and muscular system (46 times) and defects of abdominal wall (omphalocoele 10 times, gastoschisis 25 times). A detailed analysis of six types of congenital malformations revealed that prenatal detection of congenital malformations increases with time and prenatal diagnostics signifi cantly participates in the total detection of congenital malformations. The percentage of prematurely terminated pregnancies from the total number of diagnosed malformations is almost 100% in anencephaly, 50-60% in spina bifi da, 50-60% in omphalocoele, 70-90% in gastroschisis, 20-30% in renal agenesis/ hypoplasia and 60-70% in Down syndrome. Conclusion: In the period of observation there were increasing numbers of prenatally diagnosed congenital malformations. A difference develops between the total number of prenatally diagnosed cases and those diagnosed prenatally and terminated. There is an increasing number of non-terminated cases (decision of the pregnant woman, multiple pregnancies, late detection of the congenital malformations). The effi ciency of prenatal diagnosis in the observed period was in the range of 50-100% in relation to the type and severity of the congenital malformations.

        Key words: congenital malformations, prenatal diagnostics, anencephaly, spina bifi da, omphalocoele, gastroschisis, renal agenesis and hypoplasia, Down syndrome