The Level of Free Fetal DNA as Precise Noninvasive Marker for Chromosomal Aneuploidies: First Results from BALTIC Region.

Background and objectives: Noninvasive prenatal testing (NIPT), which has been introduced clinically since 2011, uses the circulating cell-free fetal DNA in the maternal blood to evaluate the risk of a chromosomal anomaly. The aim of this study was to examine the effectiveness of NIPT using a single nucleotide polymorphism method. Materials and Methods: A retrospective study was conducted between 2013 and 2019. The Natera Panorama test was used to analyze the risk of trisomies 21, 18, 13, X monosomy, trisomy, and other sex chromosome abnormalities. A positive result of NIPT for aneuploidy was confirmed by invasive testing. Results: 850 women with a singleton pregnancy participated in the study. The median fetal fraction was 9.0%. The fetal fraction was lower in the no-call group (3.1%) compared with the group that received a call (9.1%) (p < 0.001). A positive correlation was determined between the gestational age and the fetal fraction (r = 0.180, p < 0.001). The overall positive predictive value (PPV) of NIPT for trisomy 21 (n = 9), trisomy 18 (n = 3) and XYY syndrome (n = 1) was 100%. Conclusions: The results of present study showed 100% PPV effectiveness of NIPT Panorama test detecting trisomies of 21 and 18 chromosomes, as well as XYY syndrome in the studied cohort. Therefore, NIPT due to its high PPV, significantly reduces the need for invasive testing, thereby reducing the risk of miscarriage and stillbirth.