What is a nuchal translucency (NT) test?
The nuchal translucency test measures the nuchal fold thickness, which is an area of tissue at the back of a fetus’s neck. The purpose of this measurement is to assess the risk of Down syndrome and other genetic abnormalities in the baby.
How is the test performed?
The sonographer will use ultrasound to measure the nuchal fold. All unborn babies have fluid at the back of their necks. In babies with Down syndrome or other genetic abnormalities, there is generally more fluid, which makes the nuchal fold appear thicker.
Often times, the mother will also have a blood test, which helps determine if the baby could have Down syndrome or another genetic disorder.
How do I prepare for this test?
1 hour and 20 minutes prior to the exam, you should empty your bladder and then drink 12 oz. of water. Finish drinking the water 1 hour prior to the exam. do not empty your bladder again until after the exam is completed.
What should I expect during this test?
You may feel some discomfort from pressure on your bladder during the ultrasound. You should not feel any pain.
Why is this test performed?
A nuchal translucency is normally done between the 11th and 14th week of pregnancy to screen your baby for Down syndrome and other genetic abnormalities.
Normal results range from 2mm at 11weeks to 2.8mm at 14 weeks, indicating that is very unlikely your baby has Down syndrome or another genetic abnormality.
More fluid in the back of the neck means there is a higher risk of Down syndrome, but it does not confirm a diagnosis of Down syndrome. Additional testing, such as an amniocentesis will often be performed following abnormal results.
Are there any risks associated is a nuchal translucency test?
There are no risks associated with a nuchal translucency test.