Abstract
The leading cause of malformations of the human fetus is chromosomal abnormalities. In connection with this, one of the main tasks of medical genetics is to reduce the incidence of chromosomal pathology in the human population. To solve this problem, invasive and non-invasive methods of prenatal diagnosis are used. The article presents the results of biochemical screening of blood serum of pregnant women and, in particular, the results of a cytogenetic study of the fetus of pregnant women at risk. Biochemical screening was conducted for 30335 pregnant women. The screening was conducted in the I and II trimester at 11-13 and 14-20 weeks of pregnancy. In the first trimester, a "double test" was used to determine the level of the β-subunit of the hCG hormone and the pregnancy-related plasma protein RAPP-A. In the second trimester, a "triple test" was used - determination of the level of AFP, hCG and free estriol E3. Based on the use of the enzyme immunoassay, the results of the indices of these biomarkers determined the possibility of the presence of chromosomal abnormalities in the fetus. According to biochemical screening, a risk group was identified from 662 (2.2%) pregnant women who underwent invasive diagnosis. Cytogenetic studies of metaphase cells of villi chorion were carried out. Fetal development disorders were detected in 41 cases, which was 6.2%. In two cases, cystic gigrum and spina bifida were identified. Karyotype disorders were found in 39 (5.9%) of the fetuses. Among them, the karyotype of Down syndrome was revealed in 29 cases, which was 74.4%. Comparative analysis by age factor showed an increase in the frequency of fetuses with Down's syndrome by 2.2 times in pregnant women 30 and older. Key words: biochemical screening, biomarkers, enzyme immunoassay, chromosomal abnormalities, fetal karyotype.