Twin pregnancies are common and associated with pregnancy complications and adverse outcomes. Prenatal clinical management is intensive and has been hampered by inferior screening and less acceptable invasive testing. For aneuploidy screening, meta-analyses show that non-invasive prenatal testing (NIPT) through analysis of cell-free DNA (cf-DNA) is superior to serum and ultrasound-based tests. The positive predictive value for NIPT is driven strongly by the discriminatory power of the assay and only secondarily by the prior risk. Uncertainties in a priori risks for aneuploidies in twin pregnancies are therefore of lesser importance with NIPT. Additional information on zygosity can be obtained using NIPT. Establishing zygosity can be helpful when chorionicity was not reliably established early in pregnancy or where the there is a concern for one versus two affected fetuses. In dizygotic twin pregnancies, individual fetal fractions can be measured to ensure that both values are satisfactory. Vanishing twins can be identified by NIPT. Although clinical utility of routinely detecting vanishing twins has not yet been demonstrated, there are individual cases where cf-DNA analysis could be helpful in explaining unusual clinical or laboratory observations. We conclude that cf-DNA analysis and ultrasound have synergistic roles in the management of multiple gestational pregnancies.

中文翻译：

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双胎妊娠管理中的无创产前检测

双胎妊娠很常见，并且与妊娠并发症和不良结局有关。产前临床管理是密集的，并且受到劣质筛查和不太可接受的侵入性检测的阻碍。对于非整倍体筛查，荟萃分析表明，通过分析游离 DNA (cf-DNA) 进行的无创产前检测 (NIPT) 优于基于血清和超声的检测。NIPT 的阳性预测值主要由检测的辨别力驱动，其次是先验风险。因此，对于 NIPT，双胎妊娠非整倍体先验风险的不确定性不太重要。可以使用 NIPT 获得有关接合性的其他信息。当绒毛膜性在怀孕早期无法可靠地建立或担心一对两个受影响的胎儿时，建立接合性可能会有所帮助。在异卵双胎妊娠中，可以测量单个胎儿分数以确保两个值都令人满意。NIPT 可以识别消失的双胞胎。尽管常规检测消失双胞胎的临床效用尚未得到证实，但在个别情况下，cf-DNA 分析可能有助于解释不寻常的临床或实验室观察结果。我们得出结论，cf-DNA 分析和超声在多胎妊娠管理中具有协同作用。NIPT 可以识别消失的双胞胎。尽管常规检测消失双胞胎的临床效用尚未得到证实，但在个别情况下，cf-DNA 分析可能有助于解释不寻常的临床或实验室观察结果。我们得出结论，cf-DNA 分析和超声在多胎妊娠管理中具有协同作用。NIPT 可以识别消失的双胞胎。尽管常规检测消失双胞胎的临床效用尚未得到证实，但在个别情况下，cf-DNA 分析可能有助于解释不寻常的临床或实验室观察结果。我们得出结论，cf-DNA 分析和超声在多胎妊娠管理中具有协同作用。