The influence and reason analysis of the vanishing twin on noninvasive prenatal testing

The influence and reason analysis of the vanishing twin on noninvasive prenatal testing | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The influence and reason analysis of the vanishing twin on noninvasive prenatal testing Shuang Hu, Gege Sun, Xiangdong Kong This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4670598/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objective To investigate the influence and reason analysis of the vanishing twin on noninvasive prenatal testing. Methods Clinical data of the pregnant women with vanishing twin syndrome (VTS) who came to our department for NIPT from January 2019 to December 2023 were collected, and their general conditions, NIPT results and prenatal diagnosis results as well as the causes of test failure were analyzed. The effects of gestational week of VTS and re-sampling time slot on the positive rate of NIPT were also discussed. Results Of the 102 cases, 5 cases were NIPT positive (4.9%), among them 4 cases were sex chromosome abnormality (SCA), and 1 case was ChrX-(Z=-7.38), that is, X chromosome reduction. The karyotype and CNV-seq results were all normal after amniocentesis. Namely, all the 5 cases were false positive, and the rate was 100% (5/5). The positive rate of VT 0.05) Conclusion NIPT could be applied on VT pregnancy, prolong the time interval of fetal demise and NIPT sampling. Once established, unnecessary invasive procedures could be avoided, mitigating negative emotional impact on future mothers. NIPT VTS false positive sex chromosome abnormality SCA What's already known about this topic? Noninvasive prenatal testing (NIPT) has been broadly applied on the single pregnancy or twin pregnancy. The accuracy of trisomy 21, trisomy 18 and trisomy 13 screening is much higher than that of traditional screening methods. But less is known about the application of NIPT on the vanishing twin syndrome pregnancy, the counseling is challenging. - What does this study add? NIPT could be applied on VTS pregnancy. Even though it may increase false-positive rate and cause discordant phenotypic sex, prolong the time interval of fetal demise and NIPT sampling could avoid all these situations. Introduction Vanishing twin syndrome (VTS) refers to the spontaneous death of the embryo or one of the fetuses during twin pregnancy, which is one of the main adverse complications of twin pregnancy [1]. It can occur at any gestational week, but it is more common in the first trimester[2], accounting for up to 30% of pregnancies[3]. Studies have shown that vanishing embryos may be related to chromosomal abnormalities [4,5]. Other studies have speculated that VTS may be the role of isoimmunization, such as in Rh inconsistent twins, they found that the Rh positive fetus died, while the Rh negative fetus continued to develop [6,7]; Moreover, some studies have suggested that placental factors can also lead to the occurrence of VTS, such as abnormal placental structure [8]. With the wide application of NIPT technology in clinical practice, the accuracy of trisomy 21, trisomy 18 and trisomy 13 screening is much higher than that of traditional screening methods, regardless of single pregnancy or twin pregnancy [9,10], whilst less is known about the application of NIPT on the VTS pregnancy. There are few reports on its clinical application on the VTS, and relatively few cases are reported. Therefore, genetic counseling for VTS pregnancies is more difficult than that for conventional pregnancies. Herein we collected clinical data of pregnant women with VTS who came to our department for NIPT detection, analyzed their general conditions, NIPT results and prenatal diagnosis results, as well as the causes of detection failure, and explored the influence of gestational week and re-sampling interval of VT on the positive rate of NIPT. Our research is aimed at expanding NIPT possibilities in VTS and providing more significant information to evaluate the clinical significance of NIPT in VTS pregnancy. Materials And Methods Subject enrollment The pregnant women with VTS who came to our center for NIPT from January 2019 to December 2023 was included in this retrospective analytical data study, and the screening results of NIPT, prenatal diagnosis results and pregnancy outcomes were retrospectively analyzed. Pregnant women ranged in age from 19 to 45 years, with an average age of (30.7 ± 2.5) years old. Gestational age ranged from 12 to 22 + 6 weeks, with a mean of (18.3 ± 1.5) weeks. Inclusion criteria: Ultrasound examination revealed the disappearance of one of the twins with or without other ultrasonic abnormalities. Amniocentesis was performed on the 5 high-risk pregnant women to obtain the confirmatory diagnosis results. All pregnant women signed informed consent. This study was approved by the hospital Medical Ethics Committee. (KS-2018-KY-36) 1.1 NIPT For each pregnant woman with VTS, 10ml peripheral blood was collected and plasma cell-free DNA was extracted by using a cfDNA extraction isolation kit (Berry Genomics Corporation, Beijing, China). After the library construction was completed, the NextSeq CN500 sequencing platform (Berry Genomics Corporation, Beijing, China) was used for sequencing, and the obtained gene sequence was compared with the human reference genome and processed by the data analysis system(Berry Genomics Corporation, Beijing, China). The risk of fetal chromosome aneuploidy and copy number variations (CNVs) was determined. The risk value was evaluated by Z-value. The normal range of Z value is -3 ~ 3, and the risk level is high when Z≤-3 or Z ≥ 3. 1.2 CNV-seq DNA was extracted from 4 cases of amniotic fluid cell samples, enzyme digestion, preparation of library, computer sequencing (Nextseq CN500, USA), and comparison analysis was performed with human genome after sequencing. A special algorithm was used to obtain the CNV of each sample. Interpretation of the clinical significance of each CNVs were reference to the latest ACMG guidelines [11]. 1.3 Statistical Analysis The Fishers exact test was used to test the differences of proportions for statistical significance. P < 0.05 was considered to indicate statistical significance. Positive predictive value (PPV) was calculated as the number of cases for which the results of NIPT and invasive prenatal diagnosis were concordant. Results Epidemiological characteristics The epidemiological characteristics of pregnant women are shown in Table 1. The age of 102 VT pregnant women was (30.7 ± 2.5) years old, ranging from 19.0 to 45.0 years old, including 18 cases (17.4%) of advanced age pregnancy (≥ 35 years old), 66 cases (64.7%) conceived naturally and 36 cases (35.3%) conceived by in vitro fertilization and embryo transfer (IVF-ET). The median gestational age of VT onset was 8 weeks (5.0–14.0 weeks). The median gestational age at NIPT blood sampling was 18 weeks (13.0–21.0 weeks). Distribution of different clinical indications: 11 cases of abnormal ultrasound, 17 cases of advanced maternal age, 2 cases of high-risk prenatal serum screening, 2 cases of borderline-risk prenatal serum screening, 70 cases of voluntary screening. Fetal fractions within our study population ranged from 2.5–29%, with an average value of 11.9%, the median was 11.6%. NIPT results and prenatal diagnosis Among 102 VT pregnant women, 5 cases (4.9%) were positive, among them 4 cases were sex chromosome abnormality (SCA), and the left 1 case was ChrX- (Z=-7.38), that is, X chromosome reduction. The karyotype and CNV-seq results were normal (46, XX) after amniocentesis. The Positive Predictive Value (PPV) is 0% (0/5). Due to the low fetal fraction of cffDNA, one sample is no call. NIPT results of the remaining 96 cases were all negative. No false- negative results were found. Relationship between positive rate and gestational age of fetal demise and NIPT sampling The positive rate of VT with gestational age 0.05) The positive rate of the length of time between fetal demise and NIPT sampling 0.05) As can be seen, no clear relationship was observed. Reason analysis of re-sampling and re-testing Four samples were with no calls normally due to abnormal sex chromosome(3/4)or low fetal fraction of cffDNA༈1/4༉. All the 4 cases completed the re-sampling about 1 week after the first sampling. But all of them still failed to have reportable results. (Detailed in Table 2 ) In case 1, the first and second blood samples were collected, and the test results were all suggestive of SCA. In case 2, the fetal fraction was low, the fetal fraction of cffDNA was 2.83% at the first time and 2.58% at the second time. Case 3 refused amniocentesis because of advanced maternal age and IVF. The results of the first three sampling were all sex chromosome abnormalities, but the fourth sampling showed negative result. In case 4, the second sampling showed sex chromosome abnormalities as the first sampling. We discovered that extending the time interval to 15 weeks (case 3), false-positive results could be reduced. Two cases with only one sampling had 2 NIPT testing, because of SCA, the detailed information are in Table 3. Follow ups For the positive cases, 5 normal baby girls were born. For the low fetal fraction case, one healthy baby was born. No false negative results reported for all the negative cases. For the remaining 96 cases, 4 lose contact, 92 cases were live born. Discussion From the results described above, we found that NIPT could be applied on the VTS pregnancies. Despite the low PPV and relative high testing failure rate, which may be due to low number samples in our cohort, the best strength of our research is that we found that sex chromosomes of the demised fetal seriously interfere with the accuracy of NIPT results even the time interval of fetal demise and NIPT sampling is longer than 10 weeks, but this phenomenon could disappear when the time interval is longer than 15 weeks. The main cause of VTS is believed to be chromosomal aberrations of the demised fetus. The placenta of the aborted fetus with abnormal chromosome is not completely absorbed, so its DNA may affect the NIPT, causing no call, false-positive results or discordant phenotypic sex [ 12 ]. Some past studies declared that VTS should be excluded from cffDNA testing. However, existing studies recommend a more differentiated approach for the VT population as long as pregnancy women and laboratory are appropriately informed, they suggest that NIPT can successfully detect common autosomal aneuploidies in pregnancies affected by a VT but with a higher rate, including our data here[ 13 – 16 ]. Some researchers found that VTS was related to a false-positive NIPT result [ 17 , 18 ]. One study revealed that VT could cause 13% false-positive NIPT cases (7/54) [ 19 ]. Some other researches even found that co-twin demise, however, results in as much as 42.1% of confirmed NIPT results[ 20 ]. Our present study fully demonstrated the applications of NIPT in VTS pregnancies significantly improve the false-positive rate (5/5,100%) than that of routine NIPT clinical samples [ 21 , 22 ]. The five positive NIPT results are all about sex chromosomes. According to our local database [ 23 ], when the chrY 5 (chrYz ≤ 5 represents female) simultaneously, the analysis system may indicate Sex Chromosome Abnormality (SCA), a re-sampling is needed. When the result of the re-sampling was still SCA, the invasive prenatal diagnosis is recommended. For cases 1, 4, 5, 6 and 3 (three initial samplings), the chrY 5, thus the analysis system could not explicitly estimate chromosome X or Y aneuploidies. When the sex of the two twins is inconsistent, the deceased fetus will affect the determination of the sex of the surviving fetus by NIPT. Researchers declared that the majority of the cases of discordant suspected sex results on US and NIPT results were due to VT[ 24 ]. It was generally reported that when the demised fetus is male and the ongoing fetus is female, it is easy to misjudge the viable fetus as male [ 25 , 26 ]. In here, the viable fetuses are all girls, so we suspected that the demised fetuses are all male fetuses, continuous release of male fetal DNA caused the discrepancy of chrY 5. In order to reduce the risk of false-positive, sex discrepancy and test failure, the timing of sampling for these VT pregnancies needed to be noticed. Lots of literatures declared that the demised fetal cffDNA is tentatively assumed to be detectable up to 15 weeks after fetal demise[ 13 , 18 , 27 ] Yang Zou et al in 2021 found that re-sampling after 15 weeks of gestation could reduce the most risks of negative effects of VT[ 28 ]. From our case 3, we could learn that as time extended, the effect of demised fetal could disappear. When the time interval of fetal vanish and re-sampling is longer than 15 weeks of gestation age, we could get accurate NIPT results. Therefore, VT patients should be counseled about the risks of early testing. Further studies are needed to determine the optimal timing of NIPT in VT pregnancies in consideration of individual differences. In our series, the overall fetal fraction (FF) is similar to that of other’s study. The numerical value is between those of the singleton pregnancies and twin pregnancies with no VT [ 29 ]. When the FF is lower than 3.5%, a no-call result occurred. Possibly extending the time of re-sampling of NIPT or an ultrasound is recommended. Although NIPT on pregnant women with VTS may have, its negative exclusion ability is strong, which can reduce unnecessary invasive prenatal diagnosis. The effect of VTS on NIPT results can be reduced by extending the interval of re-sampling. Even though, we have some new findings here. Nevertheless, there are several limitations in the current study. Firstly, there are no positive results about trisomies 21, 18 and 13, which are the main target chromosomes. Secondly, the number of positive cases is small, which may due to the insufficient overall sample size. And also, these cases are all false-positives, which signify laboratory quality control needs to be strict. Thirdly, only one sample successfully displayed normal result after re-testing or re-sampling, the time interval of VT and re-sampling is unconvincing. Conclusion NIPT could be applied on VT pregnancy, prolong the time interval of fetal demise and NIPT sampling. Once established, unnecessary invasive procedures could be avoided, mitigating negative emotional impact on future mothers. Declarations Ethics approval and consent to participate: This study was approved by the Medical Ethics Committee in the First Affiliated Hospital of Zhengzhou University. All of the analyzed samples were obtained with signed informed consent. Consent for publication: All of the analyzed samples were obtained with signed informed consent. Availability of data and material: The data that support the findings of this study are available from the corresponding author upon reasonable request. Competing interests: The authors declare that they have no competing interests Funding : No grant number. This work was supported by grants from the Hospital Internal Funding from the First Affiliated Hospital of Zhengzhou University. Authors' contributions: XK and SH conceived the study, SH and GS summarized all the data and involved in histological analysis, SH and XK provided expertise for data interpretation and suggestions for manuscript preparation. SH wrote the manuscript. Acknowledgements : Not applicable References Batsry L, Yinon Y. The vanishing twin: Diagnosis and implications. Best Pract Res Clin Obstet Gynaecol 2022; 84): 66–75. Najafi K, Gholami S, Moshtagh A, Bazrgar M, Sadatian N, Abbasi G, et al. Chromosomal aberrations in pregnancy and fetal loss: Insight on the effect of consanguinity, review of 1625 cases. Mol Genet Genomic Med. 2019;8(7):e820. Gjerris AC, Tabor A, Loft A, Christiansen M, Pinborg A. First trimester prenatal screening among women pregnant after IVF/ICSI. Hum Reprod Update. 2012;4(18):350–9. Yaron Y, Pauta M, Badenas C, Soler A, Borobio V, Illanes C, et al. Maternal plasma genome-wide cell-free DNA can detect fetal aneuploidy in early and recurrent pregnancy loss and can be used to direct further workup. Hum Reprod. 2020;5(35):1222–9. Xu J, Chen M, Liu QY, Hu SQ, Li LR, Li J, et al. Detecting trisomy in products of conception from first-trimester spontaneous miscarriages by next-generation sequencing (NGS). Med (Baltim). 2020;5(99):e18731. Thurik FF, Ait Soussan A, Bossers B, Woortmeijer H, Veldhuisen B, Page-Christiaens GC, et al. Analysis of false-positive results of fetal RHD typing in a national screening program reveals vanishing twins as potential cause for discrepancy. Prenat Diagn. 2015;8(35):754–60. Masala M, Saba L, Zoppi MA, Puddu R, Picciau A, Capponi V, et al. Pitfalls in noninvasive fetal RhD and sex determination due to a vanishing twin. Prenat Diagn. 2015;5(35):506–8. Harris AL, Sacha CR, Basnet KM, James KE, Freret TS, Kaimal AJ, et al. Vanishing Twins Conceived Through Fresh In Vitro Fertilization: Obstetric Outcomes and Placental Pathology. Obstet Gynecol. 2020;6(135):1426–33. Benn P, Rebarber A. Non-invasive prenatal testing in the management of twin pregnancies. Prenat Diagn. 2021;10(41):1233–40. van der Meij KRM, Sistermans EA, Macville MVE, Stevens SJC, Bax CJ, Bekker MN, et al. TRIDENT-2: National Implementation of Genome-wide Non-invasive Prenatal Testing as a First-Tier Screening Test in the Netherlands. Am J Hum Genet. 2019;6(105):1091–101. Riggs ER, Andersen EF, Cherry AM, Kantarci S, Kearney H, Patel A, et al. Technical standards for the interpretation and reporting of constitutional copy-number variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen). Genet Med. 2020;2(22):245–57. Samura O, Okamoto A. Causes of aberrant non-invasive prenatal testing for aneuploidy: A systematic review. Taiwan J Obstet Gynecol. 2020;1(59):16–20. Hochstenbach R, Elferink MG, van Zon PHA, Lichtenbelt KD, van Harssel J, Schuring-Blom H, et al. Discordant NIPT result in a viable trisomy-21 pregnancy due to prolonged contribution to cfDNA by a demised trisomy-14 cotwin. Clin Case Rep. 2018;5(6):788–91. Schmid M, Klaritsch P, Arzt W, Burkhardt T, Duba HC, Hausler M, et al. Cell-Free DNA Testing for Fetal Chromosomal Anomalies in clinical practice: Austrian-German-Swiss Recommendations for non-invasive prenatal tests (NIPT). Ultraschall Med. 2015;5(36):507–10. Balaguer N, Mateu-Brull E, Serra V, Simon C, Milan M. Should vanishing twin pregnancies be systematically excluded from cell-free fetal DNA testing? Prenat Diagn. 2021;10(41):1241–8. van Eekhout JCA, Bekker MN, Bax CJ, Galjaard RH. Non-invasive prenatal testing (NIPT) in twin pregnancies affected by early single fetal demise: A systematic review of NIPT and vanishing twins. Prenat Diagn. 2023;7(43):829–37. Takeda E, Suzumori N, Kumagai K, Inuzuka S, Oseto K, Ohigashi Y, et al. Performance and outcomes of noninvasive prenatal testing for twin pregnancies in Japan. J Obstet Gynaecol Res. 2018;10(44):1909–14. Gromminger S, Yagmur E, Erkan S, Nagy S, Schock U, Bonnet J, et al. Fetal Aneuploidy Detection by Cell-Free DNA Sequencing for Multiple Pregnancies and Quality Issues with Vanishing Twins. J Clin Med. 2014;3(3):679–92. Suzumori N, Sekizawa A, Takeda E, Samura O, Sasaki A, Akaishi R et al. Retrospective details of false-positive and false-negative results in non-invasive prenatal testing for fetal trisomies 21, 18 and 13. Eur J Obstet Gynecol Reprod Biol 2021; 256): 75–81. Hartwig TS, Ambye L, Sorensen S, Jorgensen FS. Discordant non-invasive prenatal testing (NIPT) - a systematic review. Prenat Diagn. 2017;6(37):527–39. Zhang H, Gao Y, Jiang F, Fu M, Yuan Y, Guo Y, et al. Non-invasive prenatal testing for trisomies 21, 18 and 13: clinical experience from 146,958 pregnancies. Ultrasound Obstet Gynecol. 2015;5(45):530–8. Liehr T. False-positives and false-negatives in non-invasive prenatal testing (NIPT): what can we learn from a meta-analyses on > 750,000 tests? Mol Cytogenet. 2022;1(15):36. Zhao G, Dai P, Wang C, Liu L, Zhao X, Kong X. Clinical Application of Noninvasive Prenatal Testing for Sex Chromosome Aneuploidies in Central China. Front Med (Lausanne) 2021; 8): 672211. Scibetta EW, Gaw SL, Rao RR, Silverman NS, Han CS, Platt LD. Clinical accuracy of abnormal cell-free fetal DNA results for the sex chromosomes. Prenat Diagn. 2017;13(37):1291–7. Byers HM, Neufeld-Kaiser W, Chang EY, Tsuchiya K, Oehler ES, Adam MP. Discordant sex between fetal screening and postnatal phenotype requires evaluation. J Perinatol. 2019;1(39):28–33. Dhamankar R, DiNonno W, Martin KA, Demko ZP, Gomez-Lobo V. Fetal Sex Results of Noninvasive Prenatal Testing and Differences With Ultrasonography. Obstet Gynecol. 2020;5(135):1198–206. Niles KM, Murji A, Chitayat D. Prolonged duration of persistent cell-free fetal DNA from vanishing twin. Ultrasound Obstet Gynecol. 2018;4(52):547–8. Zou Y, Cui L, Xue M, Yan J, Huang M, Gao M, et al. Applications of noninvasive prenatal testing in vanishing twin syndrome pregnancies after treatment of assisted reproductive technology in a single center. Prenat Diagn. 2021;2(41):226–33. Kleinfinger P, Luscan A, Descourvieres L, Buzas D, Boughalem A, Serero S et al. Noninvasive Prenatal Screening for Trisomy 21 in Patients with a Vanishing Twin. Genes (Basel) 2022; 11(13). Tables Table 1 Epidemiological characteristics of pregnant women with ART and spontaneous pregnancy ARTpregnanct(n = 36) Spontaneous Pregnancy (n = 66) Gestation age of testing No. % No. % < 12 weeks 0 0 0 0 13-24weeks 36 100 66 100 Chorionic Monochorionic membrane 11 30.5% 44 66.7 Dichorionic membrane 25 69.5% 22 33.3 Maternal age <35 27 75 58 87.8 ≥ 35 9 25 8 12.2 Indications Advanced maternal age 7 19.4 10 15.1 Abnormal ultrasound 4 11.1 7 10.6 High-risk prenatal serum screening, 1 2.8 1 1.5 Borderline-risk prenatal serum screening 1 2.8 1 1.5 Voluntary screening 23 63.9 47 71.3 Total 36 66 Table 2 The gestational weeks, the ratios and Z scores of ChrY, and the NIPT results of four re-sampling cases Case 1 Case 2 Case 3 Case 4 Gestational week of VT 10 + 2 7 8 + 2 8 1st sampling Gestational week 18 + 3 15 + 2 17 + 1 17 + 5 ChrY%+ChrZ 0.0068%,15.17 0.0076%,19.07 0.0049%,6.68 0.0054%,13.40 NIPT result SCA Low fetal fraction SCA SCA 2nd sampling Gestational week 19 + 4 16 + 3 18 + 0 18 + 3 ChrY%+ChrZ 0.0058%,15.57 0.0071%, 18.03 0.0051%,9.18 0.0063%,13.23 NIPT result SCA Low fetal fraction SCA SCA 3rd sampling Gestational week 19 + 6 ChrY%+ChrZ — — 0.0044%,6.43 — NIPT result SCA 4th sampling Gestational week 23 + 6 ChrY%+ChrZ — — 0.0031%,1.89 — NIPT result Negative Tips: SCA : sex chromosome abnormality. “—”represents that cases 1, 2 and 4 were samples without the third and fourth sampling. Table 3 The ratios and Z scores of ChrY, and the NIPT results of 2 re-testing cases Case 5 Case 6 Gestational week of VT 10 + 3 7 + 4 1st testing Gestational week 17 + 3 14 + 1 ChrY%+ChrZ 0.0076%,19.07 0.0054%,7.85 NIPT result SCA SCA 2nd testing Gestational week 17 + 3 14 + 1 ChrY%+ChrZ 0.0069%,18.04 0.0046%, 7.69 NIPT results SCA SCA Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4670598","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":330759319,"identity":"ac88c480-4fd4-4849-829f-1e16b5467c55","order_by":0,"name":"Shuang Hu","email":"","orcid":"","institution":"the First Affiliated Hospital of Zhengzhou University","correspondingAuthor":false,"prefix":"","firstName":"Shuang","middleName":"","lastName":"Hu","suffix":""},{"id":330759320,"identity":"2cc44922-089e-46e8-b68c-2c6fb61aab5b","order_by":1,"name":"Gege Sun","email":"","orcid":"","institution":"the First Affiliated Hospital of Zhengzhou University","correspondingAuthor":false,"prefix":"","firstName":"Gege","middleName":"","lastName":"Sun","suffix":""},{"id":330759321,"identity":"9048cd8a-4993-4616-9cc9-770f2cf30f29","order_by":2,"name":"Xiangdong Kong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAvElEQVRIiWNgGAWjYBACCTDJZiPHz99AmpY0Y8kZB4CMBOK1HE7c0JBApBbJ9t7Dr3nKzjNuYDjA9uDjDyK0SPOcS7Occe42szlzA7vhDGJskZPIMTP42HabzbLhAJs0D9FaEtvO8RgcSGCT/kOMFmmJHOMHH9sOSIC1EOf9njNmjDPOJRtIzjjYJtmTRoQWieM9xp95yuzq+/mbj0n8sCFCCxCwQeKGgbGBOPVAwPyBaKWjYBSMglEwMgEA1lc1Bsnz0CgAAAAASUVORK5CYII=","orcid":"","institution":"the First Affiliated Hospital of Zhengzhou University","correspondingAuthor":true,"prefix":"","firstName":"Xiangdong","middleName":"","lastName":"Kong","suffix":""}],"badges":[],"createdAt":"2024-07-02 00:59:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4670598/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4670598/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":74034241,"identity":"defd9893-99f7-4504-9111-f5a512992a25","added_by":"auto","created_at":"2025-01-17 07:24:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":651534,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4670598/v1/2061fe88-b51a-4873-99b2-a16bc1e06c05.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The influence and reason analysis of the vanishing twin on noninvasive prenatal testing","fulltext":[{"header":"What's already known about this topic?","content":"\u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eNoninvasive prenatal testing (NIPT) has been broadly applied on the single pregnancy or twin pregnancy.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe accuracy of trisomy 21, trisomy 18 and trisomy 13 screening is much higher than that of traditional screening methods. But less is known about the application of NIPT on the vanishing twin syndrome pregnancy, the counseling is challenging.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003ch2\u003e- What does this study add?\u003c/h2\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eNIPT could be applied on VTS pregnancy.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eEven though it may increase false-positive rate and cause discordant phenotypic sex, prolong the time interval of fetal demise and NIPT sampling could avoid all these situations.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eVanishing twin syndrome (VTS) refers to the spontaneous death of the embryo\u0026nbsp;or one of the fetuses during twin pregnancy, which is one of the main adverse complications of twin pregnancy\u0026nbsp;[1]. It can occur at any gestational week, but it is more common in the first trimester[2], accounting for up to 30% of pregnancies[3]. Studies have shown that vanishing embryos may be related to chromosomal abnormalities\u0026nbsp;[4,5]. Other studies have speculated that VTS may be the role of isoimmunization, such as in Rh inconsistent twins, they found that the Rh positive fetus died, while the Rh negative fetus continued to develop\u0026nbsp;[6,7]; Moreover, some studies have suggested that placental factors can also lead to the occurrence of VTS, such as abnormal placental structure\u0026nbsp;[8].\u003c/p\u003e\n\u003cp\u003eWith the wide application of NIPT technology in clinical practice, the accuracy of trisomy 21, trisomy 18 and trisomy 13 screening is much higher than that of traditional screening methods, regardless of single pregnancy or twin pregnancy\u0026nbsp;[9,10], whilst less is known about the application of NIPT on the VTS pregnancy. There are few reports on its clinical application on the VTS, and relatively few cases are reported. Therefore, genetic counseling for VTS pregnancies is more difficult than that for conventional pregnancies.\u003c/p\u003e\n\u003cp\u003eHerein we collected clinical data of pregnant women with VTS who came to our department for NIPT detection, analyzed their general conditions, NIPT results and prenatal diagnosis results, as well as the causes of detection failure, and explored the influence of gestational week and re-sampling interval of VT on the positive rate of NIPT. Our research is aimed at expanding NIPT possibilities in VTS and providing more significant information to evaluate the clinical significance of NIPT in VTS pregnancy.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cp\u003eSubject enrollment\u003c/p\u003e\u003cp\u003eThe pregnant women with VTS who came to our center for NIPT from January 2019 to December 2023 was included in this retrospective analytical data study, and the screening results of NIPT, prenatal diagnosis results and pregnancy outcomes were retrospectively analyzed. Pregnant women ranged in age from 19 to 45 years, with an average age of (30.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5) years old. Gestational age ranged from 12 to 22\u0026thinsp;+\u0026thinsp;6 weeks, with a mean of (18.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5) weeks. Inclusion criteria: Ultrasound examination revealed the disappearance of one of the twins with or without other ultrasonic abnormalities. Amniocentesis was performed on the 5 high-risk pregnant women to obtain the confirmatory diagnosis results. All pregnant women signed informed consent. This study was approved by the hospital Medical Ethics Committee. (KS-2018-KY-36)\u003c/p\u003e\u003cp\u003e1.1 NIPT\u003c/p\u003e\u003cp\u003eFor each pregnant woman with VTS, 10ml peripheral blood was collected and plasma cell-free DNA was extracted by using a cfDNA extraction isolation kit (Berry Genomics Corporation, Beijing, China). After the library construction was completed, the NextSeq CN500 sequencing platform (Berry Genomics Corporation, Beijing, China) was used for sequencing, and the obtained gene sequence was compared with the human reference genome and processed by the data analysis system(Berry Genomics Corporation, Beijing, China). The risk of fetal chromosome aneuploidy and copy number variations (CNVs) was determined. The risk value was evaluated by Z-value. The normal range of Z value is -3\u0026thinsp;~\u0026thinsp;3, and the risk level is high when Z\u0026le;-3 or Z\u0026thinsp;\u0026ge;\u0026thinsp;3.\u003c/p\u003e\u003cp\u003e1.2 CNV-seq\u003c/p\u003e\n\u003cp\u003eDNA was extracted from 4 cases of amniotic fluid cell samples, enzyme digestion, preparation of library, computer sequencing (Nextseq CN500, USA), and comparison analysis was performed with human genome after sequencing. A special algorithm was used to obtain the CNV of each sample. Interpretation of the clinical significance of each CNVs were reference to the latest ACMG guidelines [11].\u003c/p\u003e\n\u003cp\u003e1.3 Statistical Analysis\u003c/p\u003e\u003cp\u003eThe Fishers exact test was used to test the differences of proportions for statistical significance. P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered to indicate statistical significance. Positive predictive value (PPV) was calculated as the number of cases for which the results of NIPT and invasive prenatal diagnosis were concordant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cb\u003eEpidemiological characteristics\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe epidemiological characteristics of pregnant women are shown in Table\u0026nbsp;1. The age of 102 VT pregnant women was (30.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5) years old, ranging from 19.0 to 45.0 years old, including 18 cases (17.4%) of advanced age pregnancy (\u0026ge;\u0026thinsp;35 years old), 66 cases (64.7%) conceived naturally and 36 cases (35.3%) conceived by in vitro fertilization and embryo transfer (IVF-ET). The median gestational age of VT onset was 8 weeks (5.0\u0026ndash;14.0 weeks). The median gestational age at NIPT blood sampling was 18 weeks (13.0\u0026ndash;21.0 weeks). Distribution of different clinical indications: 11 cases of abnormal ultrasound, 17 cases of advanced maternal age, 2 cases of high-risk prenatal serum screening, 2 cases of borderline-risk prenatal serum screening, 70 cases of voluntary screening.\u003c/p\u003e\u003cp\u003eFetal fractions within our study population ranged from 2.5\u0026ndash;29%, with an average value of 11.9%, the median was 11.6%.\u003c/p\u003e\u003cp\u003e\u003cb\u003eNIPT results and prenatal diagnosis\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAmong 102 VT pregnant women, 5 cases (4.9%) were positive, among them 4 cases were sex chromosome abnormality (SCA), and the left 1 case was ChrX- (Z=-7.38), that is, X chromosome reduction. The karyotype and CNV-seq results were normal (46, XX) after amniocentesis. The Positive Predictive Value (PPV) is 0% (0/5). Due to the low fetal fraction of cffDNA, one sample is no call. NIPT results of the remaining 96 cases were all negative. No false- negative results were found.\u003c/p\u003e\u003cp\u003e\u003cb\u003eRelationship between positive rate and gestational age of fetal demise and NIPT sampling\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe positive rate of VT with gestational age\u0026thinsp;\u0026lt;\u0026thinsp;10 weeks (3/72) was lower than that of VT with gestational age\u0026thinsp;\u0026ge;\u0026thinsp;10 weeks (2/29). There was no significant difference in the positive rate between the two groups. (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05) The positive rate of the length of time between fetal demise and NIPT sampling\u0026thinsp;\u0026lt;\u0026thinsp;10 weeks (3/67) was lower than that of the length of time\u0026thinsp;\u0026ge;\u0026thinsp;10 weeks (2/34). There was no significant difference in the positive rate between the two groups. (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05) As can be seen, no clear relationship was observed.\u003c/p\u003e\u003cp\u003e\u003cb\u003eReason analysis of re-sampling and re-testing\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFour samples were with no calls normally due to abnormal sex chromosome(3/4)or low fetal fraction of cffDNA༈1/4༉. All the 4 cases completed the re-sampling about 1 week after the first sampling. But all of them still failed to have reportable results. (Detailed in \u003cb\u003eTable\u0026nbsp;2\u003c/b\u003e)\u003c/p\u003e\u003cp\u003eIn case 1, the first and second blood samples were collected, and the test results were all suggestive of SCA. In case 2, the fetal fraction was low, the fetal fraction of cffDNA was 2.83% at the first time and 2.58% at the second time. Case 3 refused amniocentesis because of advanced maternal age and IVF. The results of the first three sampling were all sex chromosome abnormalities, but the fourth sampling showed negative result. In case 4, the second sampling showed sex chromosome abnormalities as the first sampling. We discovered that extending the time interval to 15 weeks (case 3), false-positive results could be reduced.\u003c/p\u003e\u003cp\u003eTwo cases with only one sampling had 2 NIPT testing, because of SCA, the detailed information are in \u003cb\u003eTable\u0026nbsp;3.\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eFollow ups\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFor the positive cases, 5 normal baby girls were born. For the low fetal fraction case, one healthy baby was born. No false negative results reported for all the negative cases. For the remaining 96 cases, 4 lose contact, 92 cases were live born.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eFrom the results described above, we found that NIPT could be applied on the VTS pregnancies. Despite the low PPV and relative high testing failure rate, which may be due to low number samples in our cohort, the best strength of our research is that we found that sex chromosomes of the demised fetal seriously interfere with the accuracy of NIPT results even the time interval of fetal demise and NIPT sampling is longer than 10 weeks, but this phenomenon could disappear when the time interval is longer than 15 weeks.\u003c/p\u003e\u003cp\u003eThe main cause of VTS is believed to be chromosomal aberrations of the demised fetus. The placenta of the aborted fetus with abnormal chromosome is not completely absorbed, so its DNA may affect the NIPT, causing no call, false-positive results or discordant phenotypic sex [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eSome past studies declared that VTS should be excluded from cffDNA testing. However, existing studies recommend a more differentiated approach for the VT population as long as pregnancy women and laboratory are appropriately informed, they suggest that NIPT can successfully detect common autosomal aneuploidies in pregnancies affected by a VT but with a higher rate, including our data here[\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eSome researchers found that VTS was related to a false-positive NIPT result [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. One study revealed that VT could cause 13% false-positive NIPT cases (7/54) [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Some other researches even found that co-twin demise, however, results in as much as 42.1% of confirmed NIPT results[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOur present study fully demonstrated the applications of NIPT in VTS pregnancies significantly improve the false-positive rate (5/5,100%) than that of routine NIPT clinical samples [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The five positive NIPT results are all about sex chromosomes. According to our local database [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], when the chrY\u0026thinsp;\u0026lt;\u0026thinsp;0.007%, the fetus is recognized as female, however, when the chrYz\u0026thinsp;\u0026gt;\u0026thinsp;5 (chrYz\u0026thinsp;\u0026le;\u0026thinsp;5 represents female) simultaneously, the analysis system may indicate Sex Chromosome Abnormality (SCA), a re-sampling is needed. When the result of the re-sampling was still SCA, the invasive prenatal diagnosis is recommended. For cases 1, 4, 5, 6 and 3 (three initial samplings), the chrY\u0026thinsp;\u0026lt;\u0026thinsp;0.007% but the chrYz\u0026thinsp;\u0026gt;\u0026thinsp;5, thus the analysis system could not explicitly estimate chromosome X or Y aneuploidies. When the sex of the two twins is inconsistent, the deceased fetus will affect the determination of the sex of the surviving fetus by NIPT. Researchers declared that the majority of the cases of discordant suspected sex results on US and NIPT results were due to VT[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. It was generally reported that when the demised fetus is male and the ongoing fetus is female, it is easy to misjudge the viable fetus as male [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn here, the viable fetuses are all girls, so we suspected that the demised fetuses are all male fetuses, continuous release of male fetal DNA caused the discrepancy of chrY\u0026thinsp;\u0026lt;\u0026thinsp;0.007% but the chrYz\u0026thinsp;\u0026gt;\u0026thinsp;5.\u003c/p\u003e\u003cp\u003eIn order to reduce the risk of false-positive, sex discrepancy and test failure, the timing of sampling for these VT pregnancies needed to be noticed. Lots of literatures declared that the demised fetal cffDNA is tentatively assumed to be detectable up to 15 weeks after fetal demise[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] Yang Zou et al in 2021 found that re-sampling after 15 weeks of gestation could reduce the most risks of negative effects of VT[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. From our case 3, we could learn that as time extended, the effect of demised fetal could disappear. When the time interval of fetal vanish and re-sampling is longer than 15 weeks of gestation age, we could get accurate NIPT results. Therefore, VT patients should be counseled about the risks of early testing. Further studies are needed to determine the optimal timing of NIPT in VT pregnancies in consideration of individual differences.\u003c/p\u003e\u003cp\u003eIn our series, the overall fetal fraction (FF) is similar to that of other\u0026rsquo;s study. The numerical value is between those of the singleton pregnancies and twin pregnancies with no VT [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. When the FF is lower than 3.5%, a no-call result occurred. Possibly extending the time of re-sampling of NIPT or an ultrasound is recommended. Although NIPT on pregnant women with VTS may have, its negative exclusion ability is strong, which can reduce unnecessary invasive prenatal diagnosis. The effect of VTS on NIPT results can be reduced by extending the interval of re-sampling.\u003c/p\u003e\u003cp\u003eEven though, we have some new findings here. Nevertheless, there are several limitations in the current study. Firstly, there are no positive results about trisomies 21, 18 and 13, which are the main target chromosomes. Secondly, the number of positive cases is small, which may due to the insufficient overall sample size. And also, these cases are all false-positives, which signify laboratory quality control needs to be strict. Thirdly, only one sample successfully displayed normal result after re-testing or re-sampling, the time interval of VT and re-sampling is unconvincing.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eNIPT could be applied on VT pregnancy, prolong the time interval of fetal demise and NIPT sampling. Once established, unnecessary invasive procedures could be avoided, mitigating negative emotional impact on future mothers.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Medical Ethics Committee in the First Affiliated Hospital of Zhengzhou University. All of the analyzed samples were obtained with signed informed consent.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll of the analyzed samples were obtained with signed informed consent.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eNo grant number. This work was supported by grants from the Hospital Internal Funding from the First Affiliated Hospital of Zhengzhou University.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eXK and SH conceived the study, SH and GS summarized all the data and involved in histological analysis, SH and XK provided expertise for data interpretation and suggestions for manuscript preparation. SH wrote the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBatsry L, Yinon Y. The vanishing twin: Diagnosis and implications. Best Pract Res Clin Obstet Gynaecol 2022; 84): 66\u0026ndash;75.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNajafi K, Gholami S, Moshtagh A, Bazrgar M, Sadatian N, Abbasi G, et al. Chromosomal aberrations in pregnancy and fetal loss: Insight on the effect of consanguinity, review of 1625 cases. Mol Genet Genomic Med. 2019;8(7):e820.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGjerris AC, Tabor A, Loft A, Christiansen M, Pinborg A. First trimester prenatal screening among women pregnant after IVF/ICSI. Hum Reprod Update. 2012;4(18):350\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYaron Y, Pauta M, Badenas C, Soler A, Borobio V, Illanes C, et al. Maternal plasma genome-wide cell-free DNA can detect fetal aneuploidy in early and recurrent pregnancy loss and can be used to direct further workup. Hum Reprod. 2020;5(35):1222\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu J, Chen M, Liu QY, Hu SQ, Li LR, Li J, et al. Detecting trisomy in products of conception from first-trimester spontaneous miscarriages by next-generation sequencing (NGS). Med (Baltim). 2020;5(99):e18731.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThurik FF, Ait Soussan A, Bossers B, Woortmeijer H, Veldhuisen B, Page-Christiaens GC, et al. Analysis of false-positive results of fetal RHD typing in a national screening program reveals vanishing twins as potential cause for discrepancy. Prenat Diagn. 2015;8(35):754\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMasala M, Saba L, Zoppi MA, Puddu R, Picciau A, Capponi V, et al. Pitfalls in noninvasive fetal RhD and sex determination due to a vanishing twin. Prenat Diagn. 2015;5(35):506\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHarris AL, Sacha CR, Basnet KM, James KE, Freret TS, Kaimal AJ, et al. Vanishing Twins Conceived Through Fresh In Vitro Fertilization: Obstetric Outcomes and Placental Pathology. Obstet Gynecol. 2020;6(135):1426\u0026ndash;33.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenn P, Rebarber A. Non-invasive prenatal testing in the management of twin pregnancies. Prenat Diagn. 2021;10(41):1233\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evan der Meij KRM, Sistermans EA, Macville MVE, Stevens SJC, Bax CJ, Bekker MN, et al. TRIDENT-2: National Implementation of Genome-wide Non-invasive Prenatal Testing as a First-Tier Screening Test in the Netherlands. Am J Hum Genet. 2019;6(105):1091\u0026ndash;101.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRiggs ER, Andersen EF, Cherry AM, Kantarci S, Kearney H, Patel A, et al. Technical standards for the interpretation and reporting of constitutional copy-number variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen). Genet Med. 2020;2(22):245\u0026ndash;57.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSamura O, Okamoto A. Causes of aberrant non-invasive prenatal testing for aneuploidy: A systematic review. Taiwan J Obstet Gynecol. 2020;1(59):16\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHochstenbach R, Elferink MG, van Zon PHA, Lichtenbelt KD, van Harssel J, Schuring-Blom H, et al. Discordant NIPT result in a viable trisomy-21 pregnancy due to prolonged contribution to cfDNA by a demised trisomy-14 cotwin. Clin Case Rep. 2018;5(6):788\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSchmid M, Klaritsch P, Arzt W, Burkhardt T, Duba HC, Hausler M, et al. Cell-Free DNA Testing for Fetal Chromosomal Anomalies in clinical practice: Austrian-German-Swiss Recommendations for non-invasive prenatal tests (NIPT). Ultraschall Med. 2015;5(36):507\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBalaguer N, Mateu-Brull E, Serra V, Simon C, Milan M. Should vanishing twin pregnancies be systematically excluded from cell-free fetal DNA testing? Prenat Diagn. 2021;10(41):1241\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evan Eekhout JCA, Bekker MN, Bax CJ, Galjaard RH. Non-invasive prenatal testing (NIPT) in twin pregnancies affected by early single fetal demise: A systematic review of NIPT and vanishing twins. Prenat Diagn. 2023;7(43):829\u0026ndash;37.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTakeda E, Suzumori N, Kumagai K, Inuzuka S, Oseto K, Ohigashi Y, et al. Performance and outcomes of noninvasive prenatal testing for twin pregnancies in Japan. J Obstet Gynaecol Res. 2018;10(44):1909\u0026ndash;14.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGromminger S, Yagmur E, Erkan S, Nagy S, Schock U, Bonnet J, et al. Fetal Aneuploidy Detection by Cell-Free DNA Sequencing for Multiple Pregnancies and Quality Issues with Vanishing Twins. J Clin Med. 2014;3(3):679\u0026ndash;92.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSuzumori N, Sekizawa A, Takeda E, Samura O, Sasaki A, Akaishi R et al. Retrospective details of false-positive and false-negative results in non-invasive prenatal testing for fetal trisomies 21, 18 and 13. Eur J Obstet Gynecol Reprod Biol 2021; 256): 75\u0026ndash;81.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHartwig TS, Ambye L, Sorensen S, Jorgensen FS. Discordant non-invasive prenatal testing (NIPT) - a systematic review. Prenat Diagn. 2017;6(37):527\u0026ndash;39.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang H, Gao Y, Jiang F, Fu M, Yuan Y, Guo Y, et al. Non-invasive prenatal testing for trisomies 21, 18 and 13: clinical experience from 146,958 pregnancies. Ultrasound Obstet Gynecol. 2015;5(45):530\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiehr T. False-positives and false-negatives in non-invasive prenatal testing (NIPT): what can we learn from a meta-analyses on \u0026gt;\u0026thinsp;750,000 tests? Mol Cytogenet. 2022;1(15):36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao G, Dai P, Wang C, Liu L, Zhao X, Kong X. Clinical Application of Noninvasive Prenatal Testing for Sex Chromosome Aneuploidies in Central China. Front Med (Lausanne) 2021; 8): 672211.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScibetta EW, Gaw SL, Rao RR, Silverman NS, Han CS, Platt LD. Clinical accuracy of abnormal cell-free fetal DNA results for the sex chromosomes. Prenat Diagn. 2017;13(37):1291\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eByers HM, Neufeld-Kaiser W, Chang EY, Tsuchiya K, Oehler ES, Adam MP. Discordant sex between fetal screening and postnatal phenotype requires evaluation. J Perinatol. 2019;1(39):28\u0026ndash;33.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDhamankar R, DiNonno W, Martin KA, Demko ZP, Gomez-Lobo V. Fetal Sex Results of Noninvasive Prenatal Testing and Differences With Ultrasonography. Obstet Gynecol. 2020;5(135):1198\u0026ndash;206.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNiles KM, Murji A, Chitayat D. Prolonged duration of persistent cell-free fetal DNA from vanishing twin. Ultrasound Obstet Gynecol. 2018;4(52):547\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZou Y, Cui L, Xue M, Yan J, Huang M, Gao M, et al. Applications of noninvasive prenatal testing in vanishing twin syndrome pregnancies after treatment of assisted reproductive technology in a single center. Prenat Diagn. 2021;2(41):226\u0026ndash;33.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKleinfinger P, Luscan A, Descourvieres L, Buzas D, Boughalem A, Serero S et al. Noninvasive Prenatal Screening for Trisomy 21 in Patients with a Vanishing Twin. Genes (Basel) 2022; 11(13).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cdiv class=\"gridtable\"\u003e\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eEpidemiological characteristics of pregnant women with ART and spontaneous pregnancy\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eARTpregnanct(n\u0026thinsp;=\u0026thinsp;36)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"9\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSpontaneous Pregnancy (n\u0026thinsp;=\u0026thinsp;66)\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eGestation age of testing\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNo.\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e%\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNo.\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"6\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e%\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"1\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;12 weeks\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"5\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e13-24weeks\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e36\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e100\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e66\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e100\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"5\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eChorionic\u003c/span\u003e\u003c/div\u003e\n \u003cdiv class=\"SimplePara\"\u003eMonochorionic membrane\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e11\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e30.5%\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"6\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e44 66.7\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eDichorionic membrane\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e25\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e69.5%\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e22 33.3\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eMaternal age\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;35\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e27\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e75\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e58\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e87.8\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026ge;\u0026thinsp;35\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e9\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e25\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e8\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e12.2\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eIndications\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eAdvanced maternal age\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e7\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e19.4\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e10\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e15.1\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eAbnormal ultrasound\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e11.1\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e7\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e10.6\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eHigh-risk prenatal serum screening,\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2.8\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.5\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eBorderline-risk prenatal serum screening\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2.8\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.5\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eVoluntary screening\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e23\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e63.9\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e47\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e71.3\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eTotal\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e36\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e66\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eThe gestational weeks, the ratios and Z scores of ChrY, and the NIPT results of four re-sampling cases\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCase 1\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCase 2\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCase 3\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCase 4\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGestational week of VT\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e10\u0026thinsp;+\u0026thinsp;2\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e7\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e8\u0026thinsp;+\u0026thinsp;2\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e8\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1st sampling\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGestational week\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e18\u0026thinsp;+\u0026thinsp;3\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e15\u0026thinsp;+\u0026thinsp;2\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e17\u0026thinsp;+\u0026thinsp;1\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e17\u0026thinsp;+\u0026thinsp;5\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eChrY%+ChrZ\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0068%,15.17\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0076%,19.07\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0049%,6.68\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0054%,13.40\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNIPT result\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eLow fetal fraction\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2nd sampling\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGestational week\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e19\u0026thinsp;+\u0026thinsp;4\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e16\u0026thinsp;+\u0026thinsp;3\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e18\u0026thinsp;+\u0026thinsp;0\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e18\u0026thinsp;+\u0026thinsp;3\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eChrY%+ChrZ\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0058%,15.57\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0071%, 18.03\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0051%,9.18\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0063%,13.23\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNIPT result\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eLow fetal fraction\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e3rd sampling\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGestational week\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e19\u0026thinsp;+\u0026thinsp;6\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eChrY%+ChrZ\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026mdash;\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026mdash;\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0044%,6.43\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026mdash;\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNIPT result\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4th sampling\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGestational week\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e23\u0026thinsp;+\u0026thinsp;6\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eChrY%+ChrZ\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026mdash;\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026mdash;\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0031%,1.89\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026mdash;\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNIPT result\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNegative\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003eTips: SCA : sex chromosome abnormality.\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003e\u0026ldquo;\u0026mdash;\u0026rdquo;represents that cases 1, 2 and 4 were samples without the third and fourth sampling.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv id=\"11\" class=\"btn-xs-small Annotation tooltipped\" data-position=\"top\" data-tooltip=\"\"\u003e\u0026nbsp;\u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eThe ratios and Z scores of ChrY, and the NIPT results of 2 re-testing cases\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCase 5\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCase 6\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGestational week of VT\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e10\u0026thinsp;+\u0026thinsp;3\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e7\u0026thinsp;+\u0026thinsp;4\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1st testing\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGestational week\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e17\u0026thinsp;+\u0026thinsp;3\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e14\u0026thinsp;+\u0026thinsp;1\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eChrY%+ChrZ\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0076%,19.07\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0054%,7.85\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNIPT result\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2nd testing\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGestational week\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e17\u0026thinsp;+\u0026thinsp;3\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e14\u0026thinsp;+\u0026thinsp;1\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eChrY%+ChrZ\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0069%,18.04\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.0046%, 7.69\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNIPT results\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSCA\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"NIPT, VTS, false positive, sex chromosome abnormality, SCA","lastPublishedDoi":"10.21203/rs.3.rs-4670598/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4670598/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective \u003c/strong\u003eTo investigate the influence and reason analysis of the vanishing twin on noninvasive prenatal testing.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods \u003c/strong\u003eClinical data of the pregnant women with vanishing twin syndrome (VTS) who came to our department for NIPT from January 2019 to December 2023 were collected, and their general conditions, NIPT results and prenatal diagnosis results as well as the causes of test failure were analyzed. The effects of gestational week of VTS and re-sampling time slot on the positive rate of NIPT were also discussed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults \u003c/strong\u003eOf the 102 cases, 5 cases were NIPT positive (4.9%), among them 4 cases were sex chromosome abnormality (SCA), and 1 case was ChrX-(Z=-7.38), that is, X chromosome reduction. The karyotype and CNV-seq results were all normal after amniocentesis. Namely, all the 5 cases were false positive, and the rate was 100% (5/5). The positive rate of VT \u0026lt; 10 weeks (3/73) was lower than that of VT ≥10 weeks (2/29). There was no significant difference in positive rate between the two groups. (P \u0026gt; 0.05)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion \u003c/strong\u003eNIPT could be applied on VT pregnancy, prolong the time interval of fetal demise and NIPT sampling. Once established, unnecessary invasive procedures could be avoided, mitigating negative emotional impact on future mothers.\u003c/p\u003e","manuscriptTitle":"The influence and reason analysis of the vanishing twin on noninvasive prenatal testing","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-24 15:44:54","doi":"10.21203/rs.3.rs-4670598/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6550ddf1-2a11-4ca7-ba7d-a618117c493d","owner":[],"postedDate":"July 24th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-01-17T07:23:49+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-24 15:44:54","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4670598","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4670598","identity":"rs-4670598","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}