If this area is thicker than normal, it can be an early sign of Down syndrome , trisomy 18 , or heart problems. The test is done between 11 and 14 weeks of pregnancy. It may be done as part of the first trimester screening test or the integrated screening test.
This test shows the chance that a baby may have a certain problem. It can't show for sure that a baby has a problem. You would need a diagnostic test, such as chorionic villus sampling CVS or amniocentesis , to find out for sure if the baby actually has a problem.
A nuchal translucency test is done to find out the chance that your developing baby fetus may be at risk for having Down syndrome or other problems. You may need a full bladder for the nuchal translucency test. If so, you'll be asked to drink water or other liquids just before the test and to avoid urinating before the test.
Talk with your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form. Most often, a nuchal translucency test is done by a specially trained ultrasound technologist.
But it may be done by a radiologist or an obstetrician who has received special training to do this test. Often you don't need to remove your clothes for the test. You can lift your shirt and push down the waistband of your skirt or pants. If you're wearing a dress, you'll be given a cloth or paper covering to put over your legs during the test.
If you need a full bladder for the test, tell your doctor or ultrasound technologist if your bladder is so full that you're in pain. When the test is done, the gel is wiped off your skin. You can urinate as soon as the test is done. During a nuchal translucency test, you may have a feeling of pressure in your bladder. The gel may feel cool when it is first put on your belly. You'll feel a light pressure from the transducer as it passes over your belly.
There are no known risks linked with a nuchal translucency test, either to you or the baby. But you may feel anxious if the test shows there is an increased chance that your baby may have a problem. Ultrasound is a safe way to check for problems and get information about your developing baby. It doesn't use X-rays or other types of radiation that may harm the baby.
Your doctor will look at the results of the nuchal translucency test to see if the area at the back of the baby's neck is thicker than normal. You may not receive information about the test right away.
The lab will use this information to calculate the chances that your pregnancy is affected with trisomy 21 Down syndrome or trisomy If your NT measurement is increased , ie 3. Close Alert Banner. Decrease text size Default text size Increase text size. Print This Page. Facebook LinkedIn Twitter Email. Nuchal Translucency Ultrasound. How to get a NT ultrasound If you choose to have a NT ultrasound, your health care provider will arrange it for when you are 11 weeks 2 days to 13 weeks 3 days gestation.
Zoom in to locate a NT ultrasound facility near you. As you zoom in, you'll see the name and street address of each facility. The NT scan alone will detect about 70 to 80 percent of babies with DS depending on which study you look at.
The detection rate for the NT scan plus a first-trimester blood test ranges from 79 to 90 percent. Most tests will include both the NT scan and the blood test. This does not mean that a screen-positive baby has a 79 to 90 percent chance of having DS.
It just means that 79 to 90 percent of babies who have DS will have screening results that are suspicious enough to recommend diagnostic testing. And 5 to 21 percent of babies who have DS will be determined to be at normal risk — that is, the results will be misleading. Screening tests aren't perfect. They don't detect all cases of DS, so they may identify your baby as being at low risk when they really do have DS.
In other words, if you're carrying a baby with DS, there's a 79 to 90 percent chance that the combined screening will detect the abnormality and give you what's called a screen-positive result indicating that further testing is recommended. But it also means there's a 5 to 21 percent chance that the tests will miss the DS and give you a screen-negative result.
This is called a false negative result, and it might lead you to decide against diagnostic testing that would have revealed a problem. These tests also have a 5 percent false-positive rate. A false-positive result is one that suggests that your baby is at increased risk for DS or another condition when, in fact, there's no problem.
With the help of your practitioner or a genetic counselor , you'll want to decide whether the results indicate a high enough risk that you want to have CVS or amniocentesis to get a definitive diagnosis. In making your decision, you'll need to weigh your need to know about your baby's condition against the small chance that diagnostic testing could cause a miscarriage. If you decide not to have diagnostic testing, you can get more information about your baby's health and development by following up with NIPT a blood test that's available to all pregnant women beginning at 10 weeks of pregnancy , the quad screen a blood test in the second trimester , and a detailed ultrasound at 18 to 20 weeks.
This ultrasound can detect "soft markers" of chromosome disorders, such as short limbs, a bright dot in the heart, a bright bowel, and certain problems in the kidneys. It can also look for anatomical defects, such as spina bifida. BabyCenter's editorial team is committed to providing the most helpful and trustworthy pregnancy and parenting information in the world.
When creating and updating content, we rely on credible sources: respected health organizations, professional groups of doctors and other experts, and published studies in peer-reviewed journals. We believe you should always know the source of the information you're seeing. Learn more about our editorial and medical review policies. Prenatal genetic screening tests. American College of Obstetricians and Gynecologists. March of Dimes. Down syndrome.
Nuchal translucency test. What tests might I need during pregnancy? Should I have a screening test for Down syndrome during pregnancy? Join now to personalize. The NT scan is an ultrasound done in the first trimester to determine your baby's risk of having Down syndrome and some other chromosomal abnormalities.
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