Nuchal Translucency Test

The nuchal translucency scan is part of your first trimester screen and is performed around 11-14 weeks of pregnancy in combination with a blood test to screen your baby for signs of chromosomal disorders such as Down syndrome.

There are several factors that help to assess your risk of having a baby with Down syndrome along with the scan itself. His heart rate will be monitored (babies with a high heart rate are more likely to have Down syndrome); your age will be factored in and a blood sample will be taken.

During the scan, fluid beneath the skin at the back of your baby’s neck will be measured – babies with Down syndrome tend to have have a thicker layer of fluid in this part of their bodies. The scan identifies 85 percent of babies with the abnormality, but around 5 percent of normal pregnancies will get a positive test result.

It’s important to remember that this is a screening test and can’t diagnose abnormalities. If your risk is high you may be offered a diagnostic test called chorionic villus sampling (CVS), which can be carried out between weeks 10 and 13; or an amniocentisis between weeks 14 and 20.

The information in this feature is intended for educational purposes only. If you have any concerns about your health, the health of your child or the health of someone you know, please consult with a doctor or other healthcare professional.