CLINICAL, ULTRASOUND AND CYTOGENETIC CHARACTERISTICS OF FETUSES WITH INCREASED NUCHAL TRANSLUCENCY THICKNESS IN THE FIRST TRIMESTER OF PREGNANCY

Background: Improving programs for early prenatal detection of congenital malformations remains a relevant scientific and practical problem. The prevalence of congenital anomalies in Ukraine is 23.7:1000 among live-born babies, and there is no significant decrease in it. The aim of this study was to compare clinical, ultrasound and cytogenetic data in swollen fetuses with increased nuchal translucency (NT) thicknesses from the group of pregnant women in the first trimester at high genetic risk to optimize the algorithm of prenatal diagnostics. Materials and Methods: Clinical examinations, ultrasound diagnostics, invasive methods of prenatal diagnostics (chorion biopsy, amniocentesis), genetic testing techniques, such as karyotyping and FISH, genetic counseling and statistical analysis were carried out. The results of complex examinations of 127 fetuses with an increased NT thickness from the group of pregnant women were analyzed. Fetuses were divided into two groups with an NT thickness of 2.5–3.5 mm (group 1) (38 cases) and with an NT above 3.5 mm (group 2)(89 cases). Results: Among pregnancies with fetuses with an increased NT thickness, there were 65.4% cases of adverse outcomes with chromosomal pathology (69.9%), congenital malformations of non-chromosomal etiology (25.3%) and pregnancy loss (4.8%). The frequency of chromosomal abnormalities in fetuses of group 1 was 55.3% and 41.6% in group 2. Congenital malformations of various systems and organs in fetuses, the most frequent of which were cardiac defects, were diagnosed. The ratio of congenital heart defects in the fetuses of groups 1 and 2 was 23.7% and 43.8%, respectively (p=0.03; OR=0.40). Conclusion: There is no significant difference between the frequency of chromosomal abnormalities in the fetuses of group 1 compared to group 2, which indicates a high informative value of an increased NT thickness, including the thickness of 2.5–3.5 mm in fetuses in the first trimester as a marker of chromosomal pathology. A significantly higher incidence of congenital malformations of non-chromosomal etiology was found in fetuses with venous duct pathology and NT thickness over 3.5 mm compared to fetuses with the same pathology and NT thickness of 2.5–3.5 mm. Proposed changes to the management algorithm for pregnant women with swollen fetuses include mandatory congenital heart defects screening in the first trimester.