Fig. 2From: Utility of fetal facial markers on a second trimester genetic sonogram in screening for Down syndrome in a high-risk Thai populationThe distribution of facial ultrasound markers in the study euploid fetuses and fetuses with Down syndrome. Legend: PT, NBL, and PT/NBL and NBL/PT ratios according to gestational age of 340 euploid fetuses (black circles) and 11 fetuses with Down syndrome (red circles). PT prenasal thickness; NBL nasal bone length.Back to article page