First-trimester ductus venosus velocimetry in relation to nuchal translucency thickness and fetal karyotype.

Aim: To evaluate first-trimester ductus venosus flow in relation to nuchal translucency (NT) and fetal karyotype.

Methods: Ductus venosus flow was measured in fetuses with NT greater than or equal to the 95th centile (group A) and in fetuses with NT less than the 95th centile (group B). The waveforms were classified as normal if the lowest forward velocity during atrial contraction (ACV) was positive and abnormal if it was absent or negative.