Evaluation of The Relationship between Cell-Free DNA Fetal Fraction of The Circulatory System and Fetal and Maternal Pregnancy Prognosis: A Prospective Study.

Background: Non-invasive prenatal testing (NIPT), sometimes called noninvasive prenatal screening (NIPS), is a non-invasive prenatal genetic test using cell-free DNA in maternal blood. This method is used to diagnose fetal aneuploidy disorders such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18) and Patau syndrome (trisomy 13), which causes disability disorders or significant postpartum defects. The aim of this study was to investigate the relationship between high and low fetal fraction (FF) and prognosis of maternal pregnancy.

Materials and methods: In this prospective study, after obtaining informed consent, 10 ml of blood was collected from 450 mothers with singleton pregnancies with gestational age above 11 weeks (11-16) at the request of NIPT for cell-free DNA BCT test. After obtaining the test results, maternal and embryonic results were evaluated based on the amount of non-cellular DNA FF. Data analysis was performed by using SPSS software version 21 and independent t test, chi-square statistical tests.

Results: Based on test results, 20.5% of women were nulli par. The mean FF index in the studied women was 8.3% with a standard deviation of 4.6. The minimum and maximum values were 0 and 27, respectively. The frequency of normal, low and high FFs was 73.2, 17.3 and 9.5%, respectively.

Conclusion: High FF has fewer risks to the mother and fetus than low FF. The use of FF level (high or low) can help us determining the prognosis of pregnancy and using it to better manage the pregnancy.