nuchal translucency

If you just found out that you’re pregnant, you might be trying to figure out how many prenatal tests you need to get done. The nuchal translucency scan is one of them.

Pregnancy can be quite overwhelming, especially at the beginning – and even more if you weren’t trying to conceive and it took you a few more days to figure out that you were pregnant! Besides the pregnancy symptoms and the realisation of all the changes that are coming, you will need to organise your schedule for your antenatal visit: You will need to have your first midwife appointment, a blood test… And, of course, the nuchal translucency scan. It seems like a lot, but don’t worry, because you’re going to learn all there is to know about the nuchal translucency ultrasound in this article!


What’s the nuchal translucency scan exactly? 

The nuchal translucency or NT scan is an antenatal test that measures the amount of fluid under the skin at the back of your baby’s neck via ultrasound. Don’t worry, it sounds weird, but actually, all babies have some fluid at the back of their necks. The only difference is that there is an increased amount in many babies that are later diagnosed with Down syndrome. This way, the NT screening is used to asses the risk of the baby suffering this chromosomal abnormality – it doesn’t mean the baby has it, just that there seems to be more risk than with other babies.



When is the nuchal translucency performed? 

The NT screening is typically performed between 11 weeks pregnant and 14 weeks pregnant, that is, during the very first trimester of pregnancy. In fact, you can only have it done up until week 13 day 6 of your pregnancy. And why? Well, before, your little one would be too little to measure anything, and after that, the fluid could have been absorbed and the test would not be accurate.

Sometimes, the nuchal translucency is performed together with the dating scan, to the point that many doctors don’t even distinguish between them. Some other doctors do a first-trimester combined screening, together with the blood test to measure the hCG hormone and the PAPP-A protein.

Do I need to do the nuchal translucency?

All future mummies are offered the nuchal translucency: It is not an invasive test at all: It’s just like a regular ultrasound, and you will get valuable information that may later help you decide if you need an amniocentesis or a chorionic villus sampling (CVS), that will give you an accurate result on whether your baby has Down syndrome.

The nuchal translucency doesn’t entail any risk of miscarriage, whereas the other two tests mentioned here do: This is why it’s important to do the nuchal translucency test; so you know whether your baby has a high enough risk for you to do the amnio test or the CVS.

Sometimes, the nuchal translucency is offered together with a blood test. 

How is the nuchal translucency scan performed?

The NT scan feels just like any other ultrasound. It is a special kind, but you won’t notice the difference. You will still get that cold substance spread on your tummy, and the sonographer will move a device around so he or she (and you!) can get to see the baby. You will feel pressure sometimes, as the sonographer tries to get a good view of the baby, but it won’t hurt.

Sometimes, the ultrasound can be performed vaginally, in the cases when the sonographer can’t get a good view of the foetus. But don’t worry: It’s equally safe.


What is a normal result? Is it accurate?

It depends, because the nuchal translucency grows as your baby does. If your baby measures between 45mm and 84mm, the NT should be lower than 2.5 for you to exclude the risk of Down syndrome almost completely, but most babies who are between 2.5 mm and 3.5m are fine. As the NT raises, so does the risk. For instance, a baby with 6 mm of NT will have a higher risk of having Down syndrome.

And how accurate is it? Well, the nuchal translucency is used to asses the risk of your baby having Down syndrome, but it won’t tell you if he has it or not. So accuracy is not an element to consider.

About the accuracy on detecting the risk, the latest statistics state that the nuchal translucency early detects 77% of the cases of babies with Down syndrome.

What if the results of my nuchal translucency aren’t good? 

First of all, don’t panic. As we have explained, the nuchal translucency isn’t the test that detects trisomy 21 or Down syndrome, but the test that detects a risk of your baby having it. So even if the results aren’t good, that doesn’t mean that your baby will have Down syndrome. In fact, most women who get bad enough results in their NT scan to be considered at high risk end up having a baby free of chromosomal abnormalities!

If you get a bad result, it means that you will have to closely monitor your pregnancy and your baby. You will need to have one of the two diagnostic tests for chromosomal abnormalities, the amniocentesis or the chorionic villus sampling (CVS). It can be scary, because they entail a small risk of miscarriage, but you will have some time to think about it and make your decision. Besides, remember that you can talk about all your doubts with your doctors and ask them all your questions. Being well informed is the most important thing.

How much is the nuchal scan?

The NT screening is routine in your antenatal care, so it will be offered to you in your NHS clinic. Of course, private facilities also provide it.

Fortunately, now that you have all this information about the nuchal translucency, you will see that you have nothing to worry about. It’s just a routine, non-invasive and totally safe procedure that will just give you some more valuable information about your little one!