To investigate the clinical value of non-invasive prenatal testing (NIPT) to screen for chromosomal abnormalities in twin pregnancies and to provide further data on NIPT manifestations in twin pregnancies. In a 4-year period, 1048 women with twin pregnancies were voluntarily prospectively tested by NIPT to screen for chromosomal abnormalities by sequencing cell-free foetal DNA (cffDNA) in maternal plasma. Positive NIPT results were confirmed by karyotyping, while negative results were followed up 42 days after delivery. Thirteen women had positive NIPT results as follows: 2 cases of trisomy 21 (T21), 1 of trisomy 18 (T18), 7 of sex chromosome aneuploidy (SCA), 1 of microdeletion, and 2 of microduplication. Of these 13 cases, 2 were true-positive cases confirmed by foetal karyotype analysis, namely, 1 case of T21 and 1 of microdeletion. Furthermore, the remaining 11 high-risk pregnant women were confirmed as false positive by foetal karyotyping. Thus, the combined positive predictive value (PPV) of NIPT screening for chromosomal abnormalities in twin pregnancies was 15.4% (2/13). There were no false-negative case via our follow-up results. Safe and rapid NIPT has a certain clinical application value; however, the PPV is limited, and the screening efficiency is not stable. Careful use should be made in the screening of chromosomal abnormalities in twin pregnancies.

中文翻译：

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1048例双胎妊娠胎儿染色体异常的无创产前检测效果

研究无创产前检测 (NIPT) 筛查双胎妊娠染色体异常的临床价值，并提供有关双胎妊娠 NIPT 表现的进一步数据。在 4 年的时间里，1048 名双胎妊娠妇女接受了 NIPT 自愿前瞻性检测，通过对母体血浆中的无细胞胎儿 DNA (cffDNA) 进行测序来筛查染色体异常。阳性 NIPT 结果通过核型分析确认，阴性结果在分娩后 42 天进行随访。13名女性NIPT阳性结果如下：21三体（T21）2例，18三体（T18）1例，性染色体非整倍体（SCA）7例，微缺失1例，微重复2例。这13例中，2例经胎儿核型分析证实为真阳性，即1例T21和1例微缺失。此外，其余11名高危孕妇经胎儿核型分析证实为假阳性。因此，NIPT 筛查双胎妊娠染色体异常的综合阳性预测值 (PPV) 为 15.4% (2/13)。通过我们的随访结果，没有出现假阴性病例。安全快速的NIPT具有一定的临床应用价值；但PPV有限，筛选效率不稳定。在双胎妊娠染色体异常筛查中应谨慎使用。安全快速的NIPT具有一定的临床应用价值；但PPV有限，筛选效率不稳定。在双胎妊娠染色体异常筛查中应谨慎使用。安全快速的NIPT具有一定的临床应用价值；但PPV有限，筛选效率不稳定。在双胎妊娠染色体异常筛查中应谨慎使用。