Nuchal Scan London

What is this?

Why have this screening?
The vast majority of babies are healthy, but some babies are born with mental or physical handicaps. One of the commonest conditions is Downs Syndrome, when a baby receives an extra chromosome 21. The medical term for this is called Trisomy 21.

Who is at risk?
Every women of any age is at risk of having a baby with a chromosomal defect. For example; a younger female of 15 years old through to a mature women of 50 years old.


We call your age, your Background Risk
Every baby has a small amount of fluid at the back of the neck. This is called Nuchal Translucency between gestations of 11 weeks through to 13 weeks + 6 days.


What happens during the scan?
Before the scan starts our Specialist Midwife or Specialist Sonographer will counsel you about the scan you are having, making sure you have informed choice about the Nuchal Screening. During the scan we will measure the amount of fluid at the back of the baby's neck (Nuchal Translucency)

Using this measurement, alongside your age, and the length of your baby from head to bottom (CRL or Crown Rump Length), a risk is calculated to determine the likeihood of your baby having a chromosomal abnormality.

We call the Nuchal, gestation age & combined with your age an Adjusted Risk

Will this scan be useful for anything else?
Other checks that we can do at the time of the scan are;

Confirm Estimated Date of Delivery (EDD)

The very best time to date your pregnancy is between 11 weeks & 13 weeks + 6 days.

Check that the baby is developing normally

We will check the fetal anatomy that is visible at this stage.

Diagnose a multiple pregnancy

It is very important that we idenitfy how many babies' you have. If there are more the one what type of Twin or Triplet pregnancy it is. Monochorionic (Identical), or Dichorionic (Non-identical).

How accurate is the Screening?
Nuchal Translucency Screening (scan) alone is approximately 80% sensitive.

Can I get a higher sensitivity?
Yes, alongside the scan we can take a small amount of your blood from your arm. We can test this to see the amount of Free Beta hGC (human Gonadotrophin Chorionic) & PAPP-A (Pregnancy Associated Plasma Protein A)

This allows an increased sensitivity to 90%.

What if I have a high risk?
If the calculation gives you an increased risk, you may be happy to continue without further investigation or you may feel you want a more definate answer. In this case we can refer directly for an invasive test, (usually Chorion Villus Sampling), carried out at a specialist centre (we refer to Kings Collage Hospital or Fetal Medicine Foundation Harley St London).

Chorion Villus Sampling (CVS) involves the examination of placenta. The reason for this is that both the baby and placenta (afterbirth) originate from the same cell and so the chromosomes present in the cells of the placenta are the same as those of the baby.

The advantage of an invasive test is that you get a definate answer which is 100% right. The disadvantage is that the test carries a 1:100 risk of causing a miscarriage, this means for every 100 CVS performed 1 pregnancy will go on to miscarry regardless of the chromosomal outcome of the test. This will be fully discussed at the time of your scan.

Apeekaboo Imaging only use software designed & researched by The Fetal Medicine Foundation.

www.fetalmedicine.com