Non-invasive cell-free fetal DNA testing for aneuploidy: multicenter study of 31 515 singleton pregnancies in southeastern China.

OBJECTIVE: To analyze the non-invasive prenatal testing (NIPT) for aneuploidy results of 31 515 singleton pregnancies in Fujian province, southeastern China, and assess its performance in low-, moderate- and high-risk pregnancies.

METHODS: Women were categorized into groups according to whether their risk for fetal abnormality was low, moderate or high. Cell-free plasma DNA extracted from peripheral blood samples was subjected to low-coverage whole-genome sequencing. Standard Z-score analysis of the mapped sequencing reads was used to identify fetal aneuploidy, including the three main trisomies (T21, T18 and T13) and sex chromosome aneuploidy (SCA). NIPT-positive results were confirmed by amniocentesis and karyotyping. The performance of NIPT for detection of T21, T18, T13 and SCA was assessed by calculating the sensitivity and specificity.

RESULTS: The rate of chromosomal abnormality detected by NIPT in the study population was 1.38%. A higher rate of chromosomal abnormality was found in the high-risk group (1.57%) compared to the moderate-risk (1.05%) and low-risk (1.18%) groups (P < 0.05). Sensitivity and specificity, respectively, were 98.96% (95/96) and 99.94% (31 274/31 292) for detection of T21, 100% (25/25) and 99.96% (31 352/31 363) for T18, 100% (7/7) and 99.97% (31 373/31 381) for T13 and 100% (61/61) and 99.74% (31 245/31 327) for SCA. Positive predictive values were high for T21 (84.07%) and T18 (69.44%) and moderate for T13 (46.67%) and SCA (42.66%).

CONCLUSION: Our findings support the application of NIPT for reliable and accurate testing of the general population of reproductive-age women for clinically significant fetal aneuploidy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.