Laboratory CERBA, 7/11 Rue de l'Équerre, 95310 Saint-Ouen-l'Aumône, France.
Obstetrics Center, Jeanne de Flandre Hospital, CHRU Lille, 59000 Lille, France.
Genes (Basel). 2022 Nov 3;13(11):2027. doi: 10.3390/genes13112027.
A vanishing twin (VT) occurs in up to 30% of early diagnosed twin pregnancies and is associated with an increased risk of fetal aneuploidy. Here, we describe our experience in a large VT population of 847 patients that underwent noninvasive prenatal testing (NIPT) for common fetal trisomies over a three-year period. All patients underwent an ultrasound examination prior to NIPT. Two comparison populations were included, namely, the singleton ( = 105,560) and the viable multiple gestation pregnancy samples ( = 9691) collected over the same period. All NIPT samples in the VT population received a result, of which 14 were high-risk for trisomy 21 (1.6%), nine for trisomy 18 (1.1%), and six for trisomy 13 (0.7%). Diagnostic testing confirmed the presence of trisomy 21 in 6/12 samples, giving a positive predictive value of 50%. One trisomy 18 case and no trisomy 13 cases were confirmed. The time between fetal demise and NIPT sampling did not appear to affect the number of true- or false-positive cases. In conclusion, NIPT is an effective screening method for trisomy 21 in the surviving fetus(es) in VT pregnancies. For trisomies 18 and 13, a positive NIPT should be interpreted carefully and ultrasound monitoring is preferrable over invasive diagnostic testing.
一个消失的双胞胎（VT）发生在多达 30%的早期诊断的双胞胎妊娠，并与胎儿非整倍体风险增加有关。在这里，我们描述了我们在一个大的 VT 人群中的经验，该人群中有 847 名患者在三年内接受了常见胎儿三体的非侵入性产前检测（NIPT）。所有患者在 NIPT 前都接受了超声检查。包括两个对照人群，即同期收集的单胎（= 105560）和有活力的多胎妊娠样本（= 9691）。VT 人群中的所有 NIPT 样本都收到了结果，其中 14 个样本的 21 三体风险较高（1.6%），9 个样本的 18 三体风险较高（1.1%），6 个样本的 13 三体风险较高（0.7%）。诊断性检测确认了 6/12 个样本中存在 21 三体，阳性预测值为 50%。1 例 18 三体病例和 1 例 13 三体病例得到证实。胎儿死亡和 NIPT 采样之间的时间似乎不会影响真阳性或假阳性病例的数量。总之，NIPT 是 VT 妊娠中存活胎儿（s）21 三体的有效筛查方法。对于 18 三体和 13 三体，阳性的 NIPT 应谨慎解读，超声监测优于有创性诊断性检测。
