An NT scan, or Nuchal Translucency scan, is a prenatal ultrasound screening performed in the first trimester of pregnancy, typically between 11 and 14 weeks gestation. It measures the thickness of the fluid-filled space at the back of the fetus's neck, known as the nuchal translucency
. The purpose of the NT scan is to assess the risk that the fetus has certain chromosomal abnormalities such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13). Increased thickness of this fluid can indicate a higher likelihood of these genetic conditions as well as some congenital heart defects
. The scan is non-invasive, painless, and usually takes about 20–30 minutes. It is often combined with other first-trimester screening tests, including blood tests and maternal age, to calculate the overall risk of chromosomal abnormalities
. While the NT scan is a screening tool and not diagnostic, abnormal results may lead to recommendations for further diagnostic testing such as non- invasive prenatal testing (NIPT), chorionic villus sampling (CVS), or amniocentesis
. In summary, the NT scan is an important early pregnancy ultrasound that helps estimate the risk of chromosomal abnormalities by measuring the fluid at the back of the fetus's neck
