Central Asian Journal of Medicine


Introduction. The analysis of fetal extracellular DNA in the blood of pregnant women can serve as one of the advanced and new directions of a non-invasive prenatal diagnosis. Concentration of extracellular DNA of a mother and a fetus in the process of pregnancy development is still unclear and not completely studied. The objective of the study is to analyze literature data and identify new markers in non-invasive prenatal diagnosis during pregnancy period. Material and methods. In the process of the present research pregnancies were examined in the dynamics of gestation. They had been under observation at the Maternity Complex №9 of Tashkent from 2014 to 2016. The research involved pregnant women depending on their gestational age, who were divided into 3 groups: the 1st group (27 pregnant with physiological course of gestation without fetal abnormalities in the I trimester), the 2nd group (29 women with the II trimester of pregnancy) and the 3rd group (21 pregnant in the III trimester of gestation). They were examined in the dynamics of gestation and had been under observation at the Maternity Complex №9 of Tashkent from 2014 to 2016. Pregnancy period ranged from 5 to 12 weeks in the 1st trimester (n=27), from 15 to 19 weeks in the 2nd trimester (n=29) and from 27 to 38 weeks in the third trimester (n=21) of pregnancy. The average age of women concluded 27,0 ±0,5 years. Results and discussion. The total concentration of extracellular DNA fraction in the plasma of pregnant women in the I trimester made 22.6±3,2 ng/ml, in the II trimester - 10.8±9,1 ng/ml and in the III trimester of pregnancy was 74.3±4,0 ng/ml. Fetal DNA is present on the cell surface of the mother's blood, but the main part of the fraction of DNA associated with the surface of the cells, presented DNA of maternal origin. The mechanisms, which observes the distribution of extracellular DNA in the blood of pregnant women, is unknown till today. Conclusion. The research establishes that the basic number as the maternal (over 90%) and fetal DNA (over 60%) is due to the surface of blood cells. During physiological pregnancy, the concentration of extracellular DNA is changing and there is a tendency to decreased levels of maternal and fetal extracellular DNA during the II trimester of pregnancy. For enhancing the informational content for noninvasive diagnostic of pathological states at different periods of pregnancy, it would seem appropriate to use the fraction of the fetal extracellular DNA associated with the surface of maternal blood cells.

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