Reproductive and Developmental Medicine (Jan 2020)
Clinical performance of cell-free fetal DNA testing for fetal aneuploidies and subchromosomal deletions/duplications in a cohort of 19,531 pregnancies
Abstract
Objective: We aim to assess the clinical performance of cell-free fetal DNA (cffDNA) testing for detecting common fetal aneuploidies as well as subchromosomal deletions/duplications and explore the pregnancy decisions in screen-positive cases. Methods: A cohort of 19,531 pregnant women was offered cffDNA testing for detection of trisomies 21, 18, and 13 (T21, T18, and T13); sex chromosome aneuploidies (SCAs); and subchromosomal deletions/duplications. Screen-positive cases were confirmed by karyotyping and single-nucleotide polymorphism array analysis. Results: A total of 47 cases failed the test. The overall screen-positive rate of chromosomal abnormalities was 1.07% (208/19,484), including 57 cases with T21, 18 cases with T18, 7 cases with T13, 106 cases with SCAs, and 20 cases of subchromosomal deletions/duplications. Positive predictive values were 91.30% (42/46), 38.46% (5/13), 33.33% (2/6), 41.33% (31/75), and 27.78% (5/18), respectively. There was no significant difference in the screening of fetal chromosomal aneuploidies in the high-risk group compared with the low-risk group (P > 0.05). All of the pregnant women who had confirmed fetal T21, T18, or T13 terminated their pregnancies, except for a case of T13 mosaic, whereas 45.16% (14/31) of women with fetal SCAs continued their pregnancies. Furthermore, 17 pregnant women with positive screens for T21, T18, or T13 without a subsequent diagnosis chose to terminate their pregnancy, whereas 29 of 31 women with SCAs chose to continue their pregnancies. Conclusions: CffDNA testing exhibited good screening accuracy for T21, T18, and T13 and also contributed to detecting fetal SCAs and subchromosomal deletions/duplications. Pregnant women with fetal 47, XXX or 47, XYY were more willing to terminate their pregnancy than those with fetal 45, X or 47, XXY.
