Nuchal Translucency Ultrasound Screening Test

During your prenatal checkups, your healthcare provider may offer some screening tests. One of these tests, performed during the first trimester, is called a nuchal translucency screening, which is basically an ultrasound that scans for certain medical conditions.

Read on to get some answers to the most frequently asked questions about nuchal translucency screening, including how the test is done, and what the results may indicate.

What Is Nuchal Translucency Screening?

Nuchal translucency screening is a type of ultrasound examination that is done in the first trimester to scan for certain medical conditions. It’s often combined with a blood test. Together, these two tests are sometimes called the “combined first trimester screening.”

Keep in mind that these and other prenatal screening tests can indicate the likelihood or chances of a baby having a certain condition, but they cannot diagnose any condition. Although your healthcare provider will likely recommend tests like the nuchal translucency screening as a regular part of your prenatal care, it’s your decision whether you want to go ahead with them or not — they are completely optional.

What Does a Nuchal Translucency Ultrasound Test For?

During a nuchal translucency screening, an ultrasound scan is used to take a measurement of the thickness of the back of the neck of your baby. If it's abnormally large, containing more fluid than usual, it may indicate Down syndrome (trisomy 21) or another genetic condition called trisomy 18.

If your healthcare provider suspects something unusual based on the results, further diagnostic testing, such as chorionic villus sampling or amniocentesis, may be recommended so that a diagnosis can be made.

It's worth being aware that prenatal screenings aren't always 100 percent accurate: false positives and false negatives can happen. You might feel more comfortable if you discuss your situation with your healthcare provider to determine whether screening or further diagnostic testing is recommended for your specific case.

Is a Nuchal Translucency Scan Necessary?

Prenatal screening tests are optional. A first trimester screening, which includes a nuchal translucency ultrasound, is considered safe.

Talk to your healthcare provider about your preferences so you can make an informed decision about whether or not you’d like a nuchal translucency test done.

When Is a Nuchal Translucency Test Done?

A nuchal translucency screening (ultrasound) is usually done in the first trimester between 10 and 14 weeks of pregnancy.

What Is an Integrated Screening?

When the results of your first trimester screenings (the nuchal translucency test and the blood test) and a set of second trimester screenings are combined, it’s called an integrated screening.

These second trimester screening tests, known as the quadruple screening (or quad screen, or multiple markers test), look for the presence of certain hormones: alpha-fetoprotein, estriol, hCG, and inhibin A.

With the results of the integrated screening in hand, your healthcare provider can better estimate whether your baby is at risk of being born with spina bifida (a neural tube defect) or a genetic disorder like Down syndrome.

If any of these screening tests indicate there is a chance of your baby being born with these medical conditions, your healthcare provider may recommend further diagnostic tests, such as chorionic villus sampling (tested in the first trimester) or amniocentesis (tested in the second trimester) to confirm or rule out the possibility.

Both of these diagnostic tests involve taking samples to diagnose or rule out certain medical conditions. With chorionic villus sampling, tissue from the placenta is tested. With amniocentesis, a little amniotic fluid is tested.

If your healthcare provider recommends a diagnostic test, you will get specific information about the risks and benefits of these tests so that you can make a decision about whether you would like to proceed with these.

Prenatal screenings, like the nuchal translucency scan, can help reassure you that your baby is developing just fine, and provides important information about your baby’s health.

If you’re ever unsure about whether a specific test might be needed in your specific case, seek the advice of your trusted healthcare provider, who can go over the specifics with you.

For more on what will be happening in the weeks, months, and trimesters of your pregnancy, check out our useful pregnancy calendar so that you’re always familiar with what’s ahead as your pregnancy progresses.

How we wrote this article

The information in this article is based on the expert advice found in trusted medical and government sources, such as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.