Clinical Review of Noninvasive Prenatal Testing: Experience from 551 Pregnancies with Noninvasive Prenatal Testing-Positive Results in a Tertiary Referral Center.

A total of 551 pregnancies with positive results for noninvasive prenatal testing (NIPT) using traditional karyotyping and chromosomal microarray analysis were analyzed. Confirmatory results, positive predictive values, etiology exploration of false-positive results, and pregnancy outcomes were recorded. The study demonstrated that NIPT performed better in predicting trisomy 21 and trisomy 18 for pregnancies with advanced maternal age than for pregnancies with young maternal age; as for trisomy 13 and sex chromosomal aneuploidy (SCA) prediction, there was no significant difference between the two groups. The positive predictive values for trisomy 21, trisomy 18, trisomy 13, and SCA showed no significant upward trend when compared based on specific age categories (an interval of 5 years), which suggested that NIPT-positive result deserves equal attention from both providers and patients regardless of maternal age. In addition, the termination rates of 45,X, 47,XXY, 47,XXX, and 47,XYY were 100% (2/2), 92.9% (26/28), 33.3% (5/15), and 9.5% (2/21), respectively, which demonstrated that the decision-making regarding pregnancies varied greatly according to the types of SCAs, and further reinforce the importance of confirmatory prenatal diagnosis. The current study also supported the viewpoint that confined placental mosaicism and maternal mosaicism were the important etiology of false-positive results.