Nuchal transluency testing

Ultralydklinikken for Gravide is the best for nuchal scan and double test because all employees working on this scan at a hospital in Copenhagen in their second act. This gives daily routine to perform the scan and objectives correctly.

Can be performed between week 11 and 4 days until weeks 13 and 6 days.

Fortunately most newborn babies are healthy. Yet in 1 of 100 births the baby has a physical or mental disorder.
The most common chromosome disorder is to have an extra copy of chromosome 21, which results in Downs Syndrome. The disorder is more common amongst the older pregnant women, but it is also found in foetuses of young women.

Nuchal translucency testing is to measure a rim of fluid in the foetuses neck

The rim is wider in foetuses that have Down syndrome. Together with the width of the rim, the mother's age and the foetuses length from head to rump a risk calculation is performed.

If the risk is higher than 1:300 we recommend an amniocentesis and we will refer you to the right hospital and department. If you live in Sweden we will refer you to Lunds University Hospital for your amniocentesis.

If the risk is less than 1:300 we don't recommend amniocentesis. If you are worried and would like some more information about the baby's risk of malformations, we recommend our early malformation scan.

 


Ultralydklinikken for Gravide

The risk calculation is made in a medical database program called 'Astraia'. It is the same program the Danish hospitals use. Astraia software is only to clinics where the staffs is certified with Foetal Medicine Foundation in London.


The risk is smaller at the birth than at 12 weeks, because about 30% of the foetuses that live past 12 weeks will still die during the remaining pregnancy as Downs Syndrome can also cause severe malformations of the heart and intestine.

While performing the ultrasound scan we also count the number of foetuses and estimate your due date. If you are carrying twins we will of course measure both foetuses nuchal rim and make separate risk calculations. If the twins are identical the risk will of course be the same.. 

Den eneste metode til at sikre sig, at det kommende barn har normale kromosomer er en moderkage- eller fostervandsprøve, men denne undersøgelse er forbundet med en abortrisiko på ca. ½%
It is important to understand that the nuchal translucency testing is a risk calculation and not a final result. It's a very good screening method that has reduced the number of invasive diagnostics to a minimum, but a low risk does not mean that there is no risk of the child having Downs Syndrome. The only method to assure that the fetus has normal chromosomes is to do the invasive amniocentesis and it is associated with an increased risk of miscarriage of 1 in 200.
An increased nuchal rim is also seen in other chromosome diseases and even small malformations of the heart.


Doubletest

The doubletest is a blood test from the pregnant woman. The blood test can be taken from full 9 weeks until 13 weeks and 6 days.

In the blood we look for the proteins: beta-hCG and PAPP-A. These are completely different to the 'trippletest' used previously. The two proteins are produced by the baby into the mother's blood. The concentration of these proteins in the mothers blood vary between normal children and children with Downs Syndrome.

If we only used the calculated risk for Downs Syndrome using the double test, we would find 60% of the foetuses with Down syndrome.

 

However if combining the calculations from the Nuchal translucency scan with the calculations of the blood test we would find 92% of the foetuses with Down syndrome. The combined test is therefore a great advantage.

It takes the laboratory about 3-4 working days to process the blood test and give us the results for the risk calculation. This means you can either have the blood test taken some days before having the scan and then after the scan get the final combined risk evaluation. Or you can have the blood test taken on the same day as the scan. We will then provide you with the risk evaluation based on your age and the scan alone that day.

Once the blood test results come back to us, we then re-calculate the risk adding this information to the equation. The final combined risk evaluation we will then e-mail you.

 

What do I get? You will receive a written rapport with:

  • The risk based on the mothers age
  • The risk based on the scan alone
  • The risk based on the combined calculation
  • A DVD with the entire examination.
  • Images of the baby printed from the scanner. Since we are an ultrasound clinic we cannot just take the blood test.

 

What is the difference between all the diagnostic tests?

  • An invasive procedure with a sampling from either the placenta or the amnion fluid. 100% of foetuses with Downs Syndrome are found
  • A non-invasive scan measuring the width of a rim of fluid in the foetuses neck region. 70% of foetuses with Downs Syndrome are found.
  • A blood test taken from the mother to measure proteins the foetus extract into the mother's blood. 60% of foetuses with Downs Syndrome are found.
  • A risk calculation that mathematically combines the results from the scan and the blood test. 92% of foetuses with Downs Syndrome are found.

The combined test is therefore a safe test that is also very good at finding the foetuses with Downs Syndrome, but it's not 100% and is merely a risk evaluation and not a definitive result.

How to understand you results:

The risk calculation will be expressed as for example: 1 in 2780. That means that if you had 2780 children that all had a nuchal translucency width and the protein concentrations equal to this baby, 1 of you babies would have Downs Syndrome. That is a low risk, but we cannot guarantee that the baby you are carrying is not that one, although it is highly unlikely.

At risks higher that 1 in 300 we recommend having the CVS or AFS. But by far most of the foetuses even with that risk will still be normal babies.