The article describes the case of prenatal diagnosis of Down’s syndrome in a 17 weeks of gestation fetus in a 39-year-old pregnant woman with the first detected giant necrotic uterine myoma and a tendency to hypercoagulable against the background of the heterozygous carriage of the Leyden mutation. At 20 weeks of gestation, due to the inability to proliferate through the natural birth canal, extirpation of the uterus with the fetus (without appendages) was carried out along the Rhine-Poros. At autopsy the diagnosis was confirmed. Timely medical and prophylactic measures allowed to avoid the development of thrombogenic complications. The article discusses the complications of the course of pregnancy with uterine myomas, as well as the features of the echographic pattern of degenerative changes in the myomatous nodes, indications for an operative delivery for uterine myomas, and the frequency of carriage of the Leiden mutation in the population. Key words: uterine myoma, Leyden mutation, ultrasound diagnosis,invasive prenatal diagnosis, Down’s syndrome.

The article presents the data of its own investigation to determine the existence of relationship formation chromosomal aberrations in the fetus with the mother’s genotype polymorphism C677T MTHFR. Materials and methods. Two groups were formed: 1 group – of women with chromosomal abnormalities in the fetus (n=131); 2 group the fruits that have been identified with the use of СA prenatal karyotyping (n=110). By way of comparison groups used women with karyotyped fruits without chromosomal abnormalities (n=139). Control group consisted of 114 healthy women who have one or more of a healthy child. In all groups performed the definition of polymorphism C677T MTHFR. Results. The genotype of C/T was significantly (p<0.01) 1.33 times more common in the group of women who had a fetus with normal karyotype and a control group of women, against women who had a fetus with CA. Genotype T/T was significantly 6.3 times (p<0.01) is more common in women selected for the prenatal diagnosis compared with women in the control group. When calculating the odds ratio shows that the risk of having a fetus with signs of chromosomal aberrations increased 7-fold (OR=7.000) in women with genotype T/T 677 MTHFR. Conclusion. Homozygous genotype for the mutant allele of MTHFR C677T T polymorphism in women with a high probability it determines the group at risk of chromosomal abnormalities in the fetus. Key words: folate metabolism, chromosomal abnormalities.