A nuchal scan or nuchal translucency (NT) scan / procedure is a sonographic prenatal screening scan (ultrasound) to detect chromosomal abnormalities in a fetus, though altered extracellular matrix composition and limited lymphatic drainage can also be detected.
A nuchal translucency screening, or NT screening, is a specialized routine ultrasound performed at the end of the first trimester of pregnancy. It helps doctors determine if a baby is statistically more likely to have a chromosomal abnormality.