Objective: The objective of the work is to make a differential analysis of the incidence and survival of children born with selected types of birth defects during their first year of life. Type of study: Retrospective demographic-epidemiological cohort analysis. Material: The study is based on unique individual data combined from three registers: births, deaths and birth defects. In all infants born in the Czech Republic in 1994 to 1999, i.e. 475 834 infants, their survival during the first year wasmonitored. The number of infants born with a congenital defect was 11 528. The number of deaths during the first year was 3 037, incl. 972 with an birth defect. For the first part of the investigation defects were selected which can be diagnosed before birth. Themortality level of children bornwith selected birth defects during different periods of their first year was studied. Results: The authors discuss the survival of children with selected birth defects during the first year of life in the CR during the period from 1994 - 1998. The infant mortality quotient in the cohort was 6.40 pro mille, in the cohort born without birth defects it was 4.46 pro mille and in the cohort born with an birth defects it was 84.6 pro mille. In these selected types of birth defects no statistically significant correlation with maternal age was found. Neonates with diagnosed birth defects - hypoplasia of the lungs, birth defects of the oesophagus, birth absence of the small intestine, anorectal atresia, hypospadia and other defects of the urinary organs - had a significantly lower birth weight and gestation period as compared with the average population. In the course of the first year of life the greatest probability of death is in children with hypoplasia of the lungs (bilateral affection) and atresia of the biliary pathways. In other types of birth defects investigated in this second part of the investigation there is a relatively large percentage of children who survive the first year. Conclusion: The majority of defects discussed in this part of the study are very difficult to diagnose prenatally. For this reason they account subsequently for a very high percentage of child morbidity, and in some cases even mortality. In some instances thus affected children are born prematurely and with a low birth weight and this implies that the problem of postnatal solution of a given birth defect may be also caused by complications ensuing from the necessary intensive neonatal care of an immature neonate with an birth defect(s).

        Key words: birth defect, incidence, Czech Republic, prenatal diagnosis, stillbirth, perinatal mortality, neonatal mortality, infant mortality, cohort