Downs Syndrome Test

[bmwnunkie]

I am fairly sure this is probably not the place to post this but it took me half an hour to find this place.

Anyway, I am a Grandfather and my Son and his Wife are having twins. She is only around 12weeks into the pregnancy. At her last scan, however ( 13/09/2021 ), the sonographer advised them that one of the twins had fluid behind the neck at 2.5 mm and given that the age of my daughter in law ( approx 38 ), the likelihood that the child would be born with Downs Syndrome would be 1 in 78. Obviously they are worried beyond distraction and not too sure what to do other than a blood test which they have had done and for which they are now awaiting the result. My question is fairly simple, to me 1/78 chance is not great but by no means a certainty. Does anyone have any experience of being in this situation who can advise what other course of action they can take in order to assess whether the baby will or will not be born Downs Syndrome?

2.5 mm is actually still within the normal range for the NT measurement. They calculate risk percentage based on that measurement, mothers age and measurement of two different hormone levels. Any risk higher than 1 in 150 is classed as medically high risk. But do be aware that even if a woman's risk factor was 1 in 151, that would fall into the low risk category. The cut off point has to be somewhere.

Because your daughter in law's risk is classed as high risk, she will be offered an amniocentesis test, where a needle is inserted into the uterus and some amniotic fluid extracted. This is tested for chromosomal abnormalities and is an actual diagnostic test. However, it does come with a small risk of miscarriage, so some women will choose not to take the test.

Additionally, it is possible to pay privately for something called a harmony test, again just a blood test. This is a more accurate indicator of risk than the NHS screening tests.

Hope this helps.

Many thanks for your kind response.

Both parents are very dismayed to say the least. This may give them some hope. The fact that a Harmony test exists is a comfort as they are seriously thinking of doing an amnio test if this blood test is inconclusive.

I'm literally going through the same issue at the moment. I've been given the odds of 1:131 and we have opted to do the CVS as the NIPT test isn't very accurate.
I have read up loads on the odds and have seen women with higher odds and the tests have come back clear. I would say it's more our age (I'm the same age).
I hope everything comes good for you.

I’m sorry your family is going through this.

I would very highly recommend a NIPT over an Amniocentesis though. The NIPT is very close to 100% accurate and carries no risk of miscarriage, whereas an amino does.

I had odds of 1:12 with my DD1. The Harmony test that previous poster have mentioned is much more accurate than the routine screening tests on the NHS, and safer than the amnio. I'm not sure if this is the blood test your daughter in law is waiting for? We had it done privately and it was about £500, I found it very useful as although it still gives probabilities, it is more of a yes or no answer. My DD did not have down's syndrome and the harmony test showed this accurately. It may be worth considering if they haven't done it as I imagine with twins the risks of amnio is a huge worry.