Biochemical markers as a part of prenatal screening of chromosomal aberrations in the Czech Republic
Abstract
Introduction: Analysis of biochemical marker is an important part of the prenatal screening examinations - calculating the risk of chromosomal aberrations of the foetus. The aim of this study is to evaluate the effectiveness of these methods in the Czech Republic.
Methods: We present a retrospective epidemiological study using the data from the National registry of congenital anomalies, which is run by the institute of Health information and statistics of the Czech Republic. Additional information on prenatally diagnosed cases are obtained actively under the patronage of Society of Medical genetics and genomics of the Czech Medical Association.
We analyzed the prenatal diagnostics of chromosomal aberrations (codes Q90-Q99) during 1994-2017 time period. Results: In 2017 the biochemical (combined, or integrated) screening test was the referral for (successful) prenatal diagnosis of Down syndrome in 92.5% of cases, while at the beginning of the selected time period it was only in 13.46% of cases.
During the selected time period - the incidence of Down syndrome in live births decreased significantly (from 7.79 per 10 000 live births in 1994 to 3.48 per 10 000 live births in 2017). The average week of gestation at the positive prenatal diagnosis of Down syndrome decreased from 20.33 in 1994 to 13.97 in 2017.
Discussion: During last twenty years the effectiveness of prenatal screening of chromosomal aberrations in the Czech Republic increased significantly. In our retrospective epidemiological study, we observed the effect of sole combined screening test of the first trimester, or integrated screening test on the increase in prenatal detection rate of Down syndrome.
The diagnostics is also now performed earlier during the pregnancy and the number of invasive diagnostics procedures decreased.