Objective:To evaluate sonographic characteristics on prenatal ultrasound study of trisomy13 and 18…
目的：对13及18三体综合征胎儿的超声表现特征和产前超声筛查价值的评价。
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CONCLUSIONS: The extent to which free fetal DNA testing can be applied as a universal screening tool for trisomy 21, 18, and 13 depends mainly on assay accuracy and cost.