Non-invasive prenatal testing (NIPT) based on fetal free DNA is a non-invasive technique to screen for common fetal aneuploidies by analyzing cell-free fetal DNA (cffDNA) in the peripheral blood of pregnant women. This technique has opened a new era of prenatal screening for its high safety and reliability. In recent years, it has been shown that NIPT can not only screen for fetal aneuploidies, but may also reveal maternal genomic abnormalities. The incidental detection of maternal tumors has aroused widespread concern in the clinical settings. The aim of this review is to systematically summarize the research progress of NIPT technique in incidental detection of maternal tumors, and to discuss its clinical significance, technical challenges, and future development direction. It has been found that multiple chromosome aneuploidies (MCAs) in NIPT detection is one of the important biomarkers suggesting occult maternal malignant tumors. In this paper, the relevant progress of NIPT technique in the incidental discovery of maternal tumors were reviewed in order to provide a reference for individualized and standardized application of NIPT technique in maternal health monitoring.
Humans ; Female ; Pregnancy ; Cell-Free Nucleic Acids/blood* ; Prenatal Diagnosis/methods* ; Incidental Findings ; Neoplasms/genetics* ; Noninvasive Prenatal Testing/methods* ; Aneuploidy ; Fetus/metabolism*

OBJECTIVE: To assess the impact of vanishing twin syndrome (VTS) on the accuracy of non-invasive prenatal testing (NIPT). METHODS: Three pregnant women who underwent NIPT testing at Guangdong Women and Children's from November 2019 to February 2020 were selected as the study subjects. The three women had either vanish twin syndrome or had undergone fetal reduction for other reasons in one of their twins, and were subsequently subject to NIPT, chromosome karyotyping, chromosome microarray analysis (CMA), and short tandem repeat (STR) analysis. This study has been approved by the Medical Ethics Committee of Guangdong Maternal and Child Health Hospital (Ethics No.: 20230132). RESULTS: Case 1 underwent selective fetal reduction at 8⁺ weeks of gestation. At 17⁺ weeks, NIPT showed a fetal DNA fraction of 2.806%, with results indicating the presence of Y chromosome and abnormal sex chromosome ratios. However, the women had subsequent uncomplicated vaginal delivery of a female infant, and no abnormality noted. Case 2 experienced spontaneous demise of one twin at 13 weeks' gestation. At 19 weeks, NIPT indicated a high risk for chromosome 21 (Z-score 4.671) in the surviving fetus, but subsequent evaluation showed no abnormality. Case 3, a dichorionic diamniotic (DCDA) twin pregnancy, underwent selective reduction at 13⁺ weeks due to fetal abnormalities in one twin. At 22⁺ weeks, NIPT for the surviving fetus indicated a high risk for chromosome 21 (Z-score 17.549), but subsequent evaluation was unremarkable. CONCLUSION In twin pregnancies, the relatively low cell-free fetal DNA (cffDNA) concentration can compromise the success rate and accuracy of NIPT compared to singleton pregnancies. Residual DNA from the demised fetus may persist for weeks following VTS or selective reduction, potentially causing false-positive NIPT results and interfering with sex chromosome prediction for the surviving fetus. Additionally, determining chorionicity is critical for reliable interpretation of NIPT results in twin pregnancies.
Adult ; Female ; Humans ; Pregnancy ; Diseases in Twins/diagnosis* ; Karyotyping ; Noninvasive Prenatal Testing/methods* ; Pregnancy, Twin ; Prenatal Diagnosis/methods*