Maternité Port Royal, AP-HP Hôpital Cochin, FHU Prema, Paris, France.
Université Paris Cité, Paris, France.
Ultrasound Obstet Gynecol. 2024 Jun;63(6):807-814. doi: 10.1002/uog.26311. Epub 2024 Apr 30.
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.
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.
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.
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.
基于母体血液游离 DNA 检测的无创性产前筛查在双胎妊娠中的表现被低估，而基于血清标志物的策略则产生较差的结果。本研究旨在评估作为一线筛查方法的无创性产前筛查在双胎妊娠中筛查 21 三体的性能。次要目标是评估其失败率和与失败相关的因素。
这是一项回顾性队列研究，纳入了 2017 年 5 月至 2019 年 10 月期间采用游离 DNA 进行无创性产前筛查的双胎妊娠。我们使用 NIPT VeriSeq® 检测进行体外诊断，并将单绒毛膜妊娠的胎儿分数截断值设定为 4%，双绒毛膜妊娠的截断值设定为 8%。临床数据和妊娠结局通过问卷由医生或助产士收集，或直接在现场检索。我们计算了无创性游离 DNA 筛查 21 三体的性能，分析了其失败率，并评估了潜在的相关因素。
在 1885 例有随访的双胎妊娠中，有 6 例（0.32%）确诊为 21 三体。无创性产前筛查 21 三体的敏感性为 100%（95%可信区间，54.1-100%），假阳性率为 0.23%（95%可信区间，0.06-0.59%）。主要失败率为 4.6%，其中 4.0%是由于胎儿分数不足。65.4%的女性接受了新的采血，成功获得了结果，使总失败率降至 2.8%。母体体重指数、筛查时的孕周以及绒毛膜性与失败的风险显著相关。
本研究进一步证明，作为 21 三体一线筛查策略的一部分，在极低的假阳性率下，双胎妊娠中的无创性产前筛查具有很高的性能。
