Prenatal ultrasonographic diagnosis of nasal bone abnormalities in three fetuses with Down syndrome.

Facial abnormalities are common in neonates with Down syndrome. This report describes nasal bone abnormalities in 3 unselected fetuses with Down syndrome detected prenatally by ultrasonography. Two of the fetuses had ultrasonographically undetectable nasal bones and 1 had a nasal bone measurement that was below the 2.5th percentile of the normal distribution for that gestational age.