目的:在双胎妊娠中使用无细胞DNA检测的非侵入性产前筛查的性能仍未得到充分评价,而基于血清标记的策略效果不佳。这项研究旨在评估双胎妊娠21三体的非侵入性产前筛查作为一线测试的性能。次要目标是评估失败率和相关因素。
方法:这项回顾性队列研究包括2017年5月至2019年10月期间使用无细胞DNA进行非侵入性产前筛查作为主要筛查策略的双胎妊娠。我们使用NIPTVeriSeq®测试进行体外诊断,并将单绒毛膜妊娠的胎儿分数临界值设定为4%,将绒毛膜妊娠的胎儿分数临界值设定为8%。通过问卷调查从医生或助产士那里收集临床数据和妊娠结局,或直接在现场检索。我们计算了21三体非侵入性无细胞DNA筛查的性能,并分析了失败率和因素。
结果:我们纳入了2577例多胎妊娠,其中1885例(84.8%)在排除消失的双胞胎和未随访的妊娠后保留。总的来说,确诊三体21例6例(0.32%)。对于21三体,敏感性为100%(95%CI,61-100%),假阳性率为0.2%(95%CI,0.07-0.6%)。由于胎儿分数不足,主要失败率为4.6%,为4%。新抽血后(59.8%的失败病例),失败率仅为1.5%。体重指数和绒毛膜与失败的风险显着相关。
结论:这项研究进一步证明了NIPS在双胞胎中的高性能,作为21三体主要筛查策略的一部分,假阳性率极低。本文受版权保护。保留所有权利。
OBJECTIVE: The performance of non-invasive prenatal screening using cell-free DNA testing of maternal blood in twin pregnancy is underevaluated, while serum marker-based strategies yield poor results. This study aimed to assess the performance of non-invasive prenatal screening for trisomy 21 in twin pregnancy as a first-tier test. Secondary objectives were to assess its failure rate and factors associated with failure.
METHODS: This retrospective cohort study included twin pregnancies in which non-invasive prenatal screening using cell-free DNA was performed as the primary screening strategy between May 2017 and October 2019. We used the NIPT VeriSeq® test for in-vitro diagnosis and set a fetal fraction cut-off of 4% for monochorionic pregnancies and 8% for dichorionic ones. Clinical data and pregnancy outcome were collected from physicians or midwives via a questionnaire or were retrieved directly on-site. We calculated the performance of non-invasive cell-free DNA screening for trisomy 21, analyzed its failure rate and assessed potentially associated factors.
RESULTS: Among 1885 twin pregnancies with follow-up, there were six (0.32%) confirmed cases of trisomy 21. The sensitivity of non-invasive prenatal screening for trisomy 21 was 100% (95% CI, 54.1-100%) and the false-positive rate was 0.23% (95% CI, 0.06-0.59%). The primary failure rate was 4.6%, with 4.0% being due to insufficient fetal fraction. A successful result was obtained for 65.4% of women who underwent a new blood draw, reducing the overall failure rate to 2.8%. Maternal body mass index, gestational age at screening as well as chorionicity were significantly associated with the risk of failure.
CONCLUSIONS: This study provides further evidence of the high performance, at an extremely low false-positive rate, of non-invasive prenatal screening in twins as part of a primary screening strategy for trisomy 21. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.