We analyzed the concentration of extracellular DNA and its fractions in the dynamics of uncomplicated pregnancy Thirty women with singleton pregnancy were examined. The concentration of total, maternal, and fetal cell-free DNA in maternal blood was measured at gestation weeks 11-14, 24-26, and 30-32. The level of total cell-free DNA was evaluated by measuring the concentration of RASSF1A gene using quantitative PCR analysis, the level of cell-free fetal DNA was assessed by determining the hypermethylated part of RASSF1A gene. The concentration of total cell-free DNA and cell-free maternal DNA did not change during the first half of pregnancy, but increased after 24-26 weeks. The level of cell-free fetal DNA increased from the first to the second and third trimester: 14.15 (2.32-36.25), 24.87 (6.29-129.32), and 32.62 (8.97-133.52) GE/ml (p<0.05), respectively. Our results characterize the dynamics of the content of cell-free DNA and its fractions during pregnancy, which should be taken into account when using cell-free DNA for prediction of placenta-associated complications.
Keywords: RASSF1A gene; cell-free fetal DNA; cell-free maternal DNA; placental dysfunction; total cell-free DNA.