Nuchal Translucency Ultrasound

Information about nuchal translucency tests

You will have to undergo many specific tests and screening during your pregnancy. The nuchal translucency ultrasound is an optional screening test that your doctor might recommend. Also called a nuchal scan or NT test, this screening looks for signs that your baby may be at heightened risk for Down syndrome, congenital heart defects and certain chromosome abnormalities. Your prenatal caregiver will administer the nuchal translucency test during your fourth month of pregnancy, between weeks 11 and 13.

What the Nuchal Translucency Scan Looks For

Your nuchal fold screening uses ultrasound equipment to measure the amount of translucent space in the area where your baby's neck is forming. Fluid accumulates in this space, called the nuchal fold, and doctors have found that babies with high fluid volumes in this area have correspondingly higher rates of Down syndrome, heart defects and chromosome deficiencies or irregularities. However, you shouldn't worry too much if your doctor finds your baby has a lot of fluid collecting. The nuchal translucency ultrasound does not definitively diagnose any problems; like other screenings, it only determines whether or not there is a heightened risk of certain birth defects. High fluid volumes do not necessarily signal any problems.

That said, if your doctor tells you that your baby does have a significantly large amount of fluid in the back of his or her neck, you may want to go ahead and have the amniocentesis and chorionic villus sampling tests to definitively find out whether or not your baby will have any birth defects. This is a highly personal decision.

The nuchal translucency ultrasound is not yet widely available, since it takes specialized equipment and specifically trained technicians to perform and analyze the image data. In the United States, it is most often performed at larger hospitals and medical centers with the funding for the specialized equipment. If it is not immediately available through your doctor's office, inquire early in your pregnancy to find the nearest location where nuchal scans are offered. You may have to be put on a waiting list, and since this is a very time-sensitive test with a small window of opportunity, it is important that you book your screening as soon as possible.