Clinical features and pregnancy outcomes of women with abnormal cell-free fetal DNA test results.

BACKGROUND: This study was performed to examine the factors affecting attitudes regarding prenatal diagnosis and clinical treatment by analyzing the clinical data of women with positive noninvasive prenatal testing (NIPT) results. METHODS: We collected clinical data for women with positive NIPT results. The women received prenatal genetic consultation. The women with true positive results received prenatal genetic counseling again, and decided whether to continue or terminate their pregnancy. RESULTS: A total of 228 women received positive NIPT results. The prenatal diagnosis was accepted in 174 cases (76.3%), and 124 women were confirmed to have true positive NIPT results. The positive predictive values (PPV) of T21/T18/T13 and fetal sex chromosome aneuploidy were 88.4% and 42.9%, respectively. All (99/99, 100%) of the women with T21/T18/T13 terminated their pregnancies, while 25.0% (6/24) of women with fetal SCA continued their pregnancies. An NIPT result of Chr(9) microduplication was obtained in one woman, which was confirmed by chromosomal microarray analysis (CMA). CONCLUSIONS: NIPT exhibited good detection accuracy for T21/T18/T13, and also contributed to identifying fetal SCA and substructural chromosomal abnormalities. With a positive NIPT result, the attitudes of pregnant women regarding prenatal diagnosis and clinical treatment are related to the severity of disease, cognitive ability, and the level of prenatal genetic counseling.

Not all chromosome aberrations can be detected by NIPT in women at advanced maternal age: A multicenter retrospective study.

OBJECTIVE: To discuss the detectability of NIPT for pregnant women at advanced maternal age (AMA), and mainly focused on how many fetal abnormalities will be missed by NIPT. METHODS: A total of 4194 women at AMA who accepted cytogenetic prenatal diagnosis were recruited in this study. All the AMA women received amniocentesis at 18-23 weeks. Combined with our detection level of NIPT and literature reports, we evaluated the detectability of NIPT. RESULTS: After cell karyotype analysis, a total of 233 (5.56%) fetuses were confirmed to have chromosomal abnormalities, including 91.0% were abnormal chromosome number and 9.0% were abnormal chromosome structure. According to the detectability of NIPT we calculated, 87.6% abnormal results could also be detected by NIPT. However, NIPT would miss 12.4% abnormal results which could be originally found by the karyotype analysis of amniotic fluid cells. The major types of missed fetal abnormalities include structural rearrangement, mosaic and triploidy. Meanwhile, there were no relationship between the detectability of NIPT and the age of AMA pregnant women. CONCLUSIONS: About 12.4% of fetal chromosomal abnormalities will be missed if NIPT completely replaces invasive prenatal diagnosis in AMA women. Fortunately, these types of fetal abnormalities missed by NIPT did not increase with the age elevating of pregnant women.