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 explore the clinical significance of trisomy 7 signaled by non-invasive prenatal testing (NIPT). METHODS: Pregnant women with high risk for trisomy 7 by NIPT from January 2017 to December 2023 were selected as the study subjects, and the results of prenatal diagnosis and follow-up were analyzed. Literature related to pregnant women with a high risk for trisomy 7 by NIPT from January 2016 to July 2024 was retrieved from China Biomedical Literature Database, Wanfang Database, China National Knowledge Infrastructure and PubMed database. Relevant information such as the incidence of trisomy 7 by NIPT, positive predictive value (PPV), and pregnancy outcomes were collected. This study has been approved by the Medical Ethics Committee of Lianyungang Maternal and Child Health Care Hospital (Ethics No. JS2022010). RESULTS: A total of 51 women with a high risk for trisomy 7 by NIPT were identified. Thirty-two of them had chosen chromosomal microarray analysis (CMA) of amniotic fluid cells, and 1 case of mosaic trisomy 7 was detected, which had yielded a PPV of 3.13%. Four women had opted termination of pregnancy, 1 had miscarriage, 4 had pre-term and/or low weight birth, whilst the remaining 42 (82.4%) had full-term delivery. In total 19 literature were retrieved, which had involved 278 cases of trisomy 7 signaled by NIPT, among which 5 fetuses with mosaic trisomy 7 (3.14%) were confirmed. Among the 211 women with follow-up outcomes, 2 (0.95%) had intrauterine growth restriction, 3 (1.42%) had abnormal fetal structure detected by ultrasound, 2 (0.95%) had miscarriage, 9 (4.27%) underwent pregnancy termination, 28 (13.27%) had preterm and/or low weight birth, whilst 167 (79.14%) had normal delivery. In 18 cases, chromosomal analysis of placental tissue was carried out, and 17 were confirmed to have mosaicism trisomy 7. CONCLUSION The PPV for trisomy 7 signaled by NIPT is extremely low. Although most of such women had a full term delivery, adverse pregnancy outcomes may still occur in a minority of cases. Clinicians should provide adequate genetic counseling for such women and recommend appropriate prenatal diagnosis strategies and optimal perinatal management plans.
Humans ; Female ; Pregnancy ; Trisomy/diagnosis* ; Chromosomes, Human, Pair 7/genetics* ; Adult ; Prenatal Diagnosis/methods* ; Noninvasive Prenatal Testing/methods* ; Pregnancy Outcome ; Clinical Relevance

OBJECTIVE: To analyze the clinical data and results of prenatal diagnosis for fetuses with high-risk for trisomy/monosomy 13 by non-invasive prenatal testing (NIPT). METHODS: Clinical data of pregnant women with fetus at a high risk for trisomy/monosomy 13 by NIPT at the First Affiliated Hospital of Zhengzhou University from May 2016 to May 2024 were reviewed, and relevant data such as Z-score, positive predictive value (PPV) and fetal fraction (FF) were analyzed to assess the correlation between them. This study was approved by the Ethics Committee of the Hospital (No. 2018-YB-08). RESULTS: 71 fetuses were found to have a high risk by NIPT, including 58 cases for trisomy 13 (T13) and 13 cases for monosomy 13 (M13). 52 women had opted invasive prenatal diagnosis and 13 cases were confirmed, which yielded a positive prediction value (PPV) of 25%. 12 fetuses were confirmed as T13 (PPV = 29.3%; 12/41), 1 was confirmed as M13 (PPV = 9.1%; 1/11). The PPV had increased along with the Z-score. Fetal faction (FF) was not correlated with the age of woman but gestational age, and was negatively correlated with the body mass index. No statistical difference was found in FF and Z-score between true- and false-positive fetuses, and there was a weak correlation between the Z-score and FF. The PPV of the NIPT could be improved by combining the results of ultrasonography. CONCLUSION The high false positive rate for T13 may be related to confined placental mosaicism, PPV is related to the Z-score, which in turn is related to FF. High-risk women are strongly recommended to undergo genetic counseling and prenatal diagnosis. Clinicians should consider relevant information such as the age of women, gestational age, indication for prenatal screening, Z-score, PPV, and FF in order to accurately interpret the result of NIPT, reduce anxiety, and avoid direct termination of the pregnancy.
Humans ; Female ; Pregnancy ; Trisomy 13 Syndrome/genetics* ; Adult ; Prenatal Diagnosis/methods* ; Noninvasive Prenatal Testing/methods*

OBJECTIVE: To analyze the results of prenatal diagnosis for fetuses with a high risk for sex chromosome aneuploidies (SCAs) indicated by non-invasive prenatal testing (NIPT), and to assess the influence of maternal chromosomal factors on the results of NIPT. METHODS: A retrospective analysis was conducted on the clinical data of 454 pregnant women with a high risk for SCAs indicated by NIPT undergoing invasive prenatal diagnosis at the Medical Genetics Center of Northwest Women's and Children's Hospital from January 2022 to September 2024. The data has included prenatal diagnosis indications, results, pregnancy outcomes, and the chromosomal results of pregnant women. RESULTS: Among the 454 women (including 10 with twin pregnancy) with a high risk for SCAs indicated by NIPT, 149 (including 4 twin cases) were diagnosed with SCAs through invasive prenatal diagnosis. These had included 47,XXX (37 cases), 47,XXY (56 cases), 47,XYY (29 cases), 45,X (1 case), 48,XXYY (1 case), mosaicism (20 cases), sex chromosome structural abnormalities (6 cases), and small-scale pathogenic copy number variations (3 cases). 383 pregnant women (including 7 with twin pregnancy) had accepted chromosomal karyotyping analysis. In total 49 cases of SCAs abnormalities were detected. Among them, 41 cases were pregnant women with SCAs but normal fetal chromosomes, which yielded a false positive rate for NIPT caused by maternal factors by 10.7%. In addition, 8 cases (including 1 twin case) had SCAs abnormalities in both the pregnant woman and the fetus. Among the 383 pregnant women, 129 cases (including 3 twin cases) of fetal SCAs were diagnosed, which yielded an overall positive predictive value (PPV) of NIPT for SCAs by 33.7% (129/383). With the 41 false positive cases caused by maternal SCAs abnormalities excluded, the PPV of NIPT for SCAs will be increased to 37.7% (129/342). Among the 454 pregnant women, twin pregnancies have accounted for 2.2% (10/454). Among the confirmed cases of SCAs abnormalities, twin cases accounted for 2.7% (4/149). Among the 383 pregnant women undergoing chromosomal karyotyping, twin cases accounted for 1.8% (7/383). Among the detected cases of chromosomal abnormalities, twin cases accounted for 2.0% (1/49). By calculation, the proportion of singleton pregnant women with a high risk for SCAs indicated by NIPT was approximately 32.1%, and the proportion of twin pregnant women was approximately 38.6%, indicating that twin pregnancies could increase the positive rate of NIPT. CONCLUSION NIPT can improve the screening efficiency for SCAs, but its PPV is limited. Therefore, pregnant women with a high risk for SCAs indicated by NIPT need to undergo invasive prenatal diagnosis for a definite diagnosis, and twin pregnancies can increase the positive rate of NIPT. The study confirmed that chromosomal abnormalities in pregnant women can significantly affect the accuracy of NIPT in detecting fetal SCAs. Therefore, when NIPT indicates SCAs abnormalities, it is recommended to simultaneously conduct chromosomal testing on the pregnant women. The combined application of chromosomal karyotyping analysis, fluorescence in situ hybridization, and copy number variation detection techniques can significantly improve the diagnostic accuracy for SCAs, especially for the detection of mosaicisms.
Humans ; Female ; Pregnancy ; Sex Chromosome Aberrations ; Adult ; Retrospective Studies ; False Positive Reactions ; Prenatal Diagnosis/methods* ; Noninvasive Prenatal Testing/methods* ; Aneuploidy ; Male ; Sex Chromosome Disorders/genetics*

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*

OBJECTIVE: To assess the clinical value of non-invasive prenatal testing (NIPT) for identifying maternal malignant tumors. METHODS: A retrospective analysis was carried out on pregnant women undergoing Non-invasive prenatal testing (NIPT) at Taizhou Hospital in Zhejiang Province from January 2018 to December 2022. The criteria included maternal copy number variations for at least two chromosomes. Clinical follow-up data were obtained for the high-risk population of maternal malignant tumors through telephone follow-up and review of electronic medical records. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: K20250339). RESULTS: Among 45 141 NIPT samples, 6 (0.013%) were suggested to have maternal malignant tumors. Follow-up information was available for 5 patients (83.3%). Two cases were diagnosed with maternal malignant tumors, including 1 myelodysplastic syndrome and 1 pelvic malignant tumor. Two cases were found to have multiple uterine fibroids and 1 was lost during follow-up. CONCLUSION The abnormal copy number indicated by NIPT may serve as an early signal for maternal malignant tumors. To establish a systematic follow-up protocol and multidisciplinary collaboration are conducive to achieving early diagnosis of tumors and improving the prognosis of patients. Based on the results of this study, it is recommended that for pregnant women with unexplained copy number variations and suspected maternal tumors by NIPT, targeted tumor screening program should be implemented to optimize their clinical management.
Humans ; Female ; Pregnancy ; Adult ; Retrospective Studies ; DNA Copy Number Variations/genetics* ; Follow-Up Studies ; Neoplasms/diagnosis* ; Noninvasive Prenatal Testing/methods* ; Pregnancy Complications, Neoplastic/diagnosis* ; Prenatal Diagnosis/methods*

OBJECTIVE: To summarize the results of prenatal diagnosis and outcome of pregnancy of fetuses with a high risk for 6p22.1.1-p21.32 duplication signaled by non-invasive prenatal screening (NIPS). METHODS: Clinical information, results of prenatal diagnosis and pregnancy for fetuses with a high risk for 6p22.1-p21.32 duplication were collected and analyzed. This study has been approved by the Medical Ethics Committee of the First Affiliated Hospital of Zhengzhou University (Ethic No. 2018-YB-08). RESULTS: Forty three pregnant women with a high risk for 6p22.1-p21.32 duplication were identified by NIPS, among whom 30 had accepted invasive prenatal diagnosis, and 27 fetuses were verified to be false positive. Three fetuses were found to have other chromosomal abnormalities, among whom two were rated to be likely benign CNV and 1 was rated to be likely pathogenic. Follow up of the 43 pregnant women revealed that 35 fetuses were normal after birth, 1 pregnancy was terminated, and 7 were lost to follow up. CONCLUSION For pregnant women with a high risk for 6p22.1-p21.32 duplication signaled by NIPS, genetic counselor need to inform them the high false positive rate and recommend invasive prenatal diagnosis and/or ultrasound examination in order to reduce the psychological and economic burdens.
Humans ; Female ; Pregnancy ; Chromosome Duplication ; Adult ; Prenatal Diagnosis/methods* ; Chromosomes, Human, Pair 6/genetics* ; Pregnancy Outcome ; Noninvasive Prenatal Testing/methods* ; Chromosome Disorders/genetics* ; Fetus/abnormalities*

OBJECTIVE: To analyze the results of noninvasive prenatal screening (NIPS) for fetal chromosome aneuploidy in twin pregnancy. METHODS: A total of 2057 women with twin-pregnancy between 12-26 weeks were recruited from Women's Hospital, Zhejiang University School of Medicine, Hangzhou Municipal Women's Hospital and Jiaxing Maternal and Child Health Hospital during February 2015 to August 2018. The cell-free DNA was extracted from the peripheral blood sample for DNA library, and non-invasive prenatal testing (NIPT) was performed by high-throughput sequencing technique. The fetal karyotype analysis or neonatal karyotype analysis was performed in pregnant women with fetal chromosome aneuploidy, and all subjects were followed up. The efficiency of NIPS testing for twin aneuploidy was calculated. RESULTS: NIPS revealed chromosome abnormalities in 11 out of 2057 twin pregnant women, 9 cases were confirmed chromosome abnormalities, 2 cases were normal and no false negative cases. In this screening, the detection rate, sensitivity, specificity, positive predictive value, false positive rate of NIPS were 100.00%, 100.00%, 99.90%, 81.82%, 0.10%. Those were 100.00%, 100.00%, 99.95%, 87.50% and 0.05% for trisomy 21, 100.00%, 100.00%, 100.00%, 100.00%, 0.00% for trisomy18, and the specificity and false positive rate for trisomy13 were 99.95% and 0.05%, respectively. CONCLUSIONS NIPS can detect fetal chromosomal aneuploidy rapidly and accurately in twin pregnancies,and it is of value in clinical application.
Aneuploidy ; Female ; Humans ; Noninvasive Prenatal Testing ; standards ; Pregnancy ; Pregnancy, Twin ; Prenatal Diagnosis ; methods ; Reproducibility of Results ; Trisomy