It is performed during the 11-13th week of pregnancy to measure the size of clear fluid, called
nuchal translucency, at the back of the baby’s neck. The aim of this scan is to screen for Down
syndrome, chromosomal or inherited conditions in the fetus, which are difficult to find in normal
scanning. Usually, universal screening with the help of USG and blood test is recommended
during this period to assess the risk of the baby.