nt,nuchal translucency

What is the Nuchal Translucency?
The nuchal translucency (also spelled nucal translucency) is a collection of fluid beneath the fetal skin in the region of the fetal neck and this is present and seen in all fetuses in early pregnancy. The fluid collection is however increased in many fetuses with Down's syndrome and many other chromosomal abnormalities. It is called a 'translucency' because on ultrasound this appears as a black space beneath the fetal skin. It is this black space that you will see measured during the ultrasound scan.

Currently the most accurate non invasive test for detecting Down syndrome during pregnancy is the measurement of the nuchal translucency with an ultrasound between 11 to 14 weeks of pregnancy. This is normally less than 2.5mm and when seen increased (greater than 2.5mm, see image on the right) may indicate the baby has Down syndrome or may indicate another chromosomal abnormality. 95% of measurements will indicate a reduced risk.