CONCLUSION: Nasal bone length expressed as MoM seems to be an useful ultrasound marker for Down syndrome in second-trimester fetuses with a high sensitivity and a low false-positive rate.

• 由鼻骨长度得到的MoM值看起来是一个很有用的超声标记,用于预测中期妊娠胎儿是否患有唐诗综合症有很高的敏感度和低的假阳性率。