1:495 risk for Down Syndrome - more tests?

[Fmlgirl]

Hi all,

Recently had my combined blood tests come back and the results are 1:495 risk for Downs and 1:17664 risk for Edwards and Pataus. Quite a huge difference in those two results.

I’m 38 years old and my BMI is 33 so not the slimmest but my morning sickness has now gone away and I feel quite good during the pregnancy. This is my first very much wanted child.

They told me at the scan that my NT measurement was 2.5 and that this was good and that they could also see a nasal bone and nothing else concerning at this stage.

Would this Down syndrome result concern you enough to have more tests done privately such as NIPT/Harmony? I think I’m a bit taken aback because my friend is 41 and her results are in the thousands.

Thanks so much all!

That seems incredibly low to me. I wouldn't worry about it

I think that your odds are normal (slightly better than normal, actually) and I personally would not have any further tests.

"Down syndrome occurs in people of all races and economic levels. The risk increases with the mother's age (1 in 1250 for a 25 year old mother to 1 in 1000 at age 31, 1 in 400 at age 35, and about 1 in 100 at age 40). However, 80% of babies with Down syndrome are born to women under age 35 years"

Some tests have a 1/100 risk of miscarriage. Weigh it up knowing that. Far higher risk than 1/495.

OP - the reason there is a huge difference in the results is that Edwards and Patau Syndrome are much rarer than Down Syndrome.

I wouldn't worry too much but would possibly have a CVS. My second child born at 37, was 1 in 2 and was fine though. Definitely wanted a CVS with those odds though. My 3rd child was 1 in about 500, I think. Again, healthy and happy.

I see it the other way round, if there are 495 babies in a row only one will have Down's syndrome.

If you were told you had a 1 in 495 chance of winning the lottery tonight would you put everything you own on it?

Yes I would - but my parents are doctors and I'm a statistician so that kind of a result would make me want to chevk it further to know whether to rule it out.

*check it further !

My risk has come back as 1 in 212 and I'm not having extra testing. The midwife and my consultant weren't concerned by my result. I'm 36, bmi of 31 with nuchal fold well within the expected range. I've since had my 20 week and 28 week scans, everything looks as expected so far.

I think it's a ratio that is entirely in keeping with your age. Doesn't guarantee anything - one baby in 495 could be affected.
Personally I would be happy with that and wouldn't test further. But it's a personal choice.

It seems a very average result for your age. More testing if that was always the plan but if not why has this made you more anxious?

It depends what a diagnosis would mean for you. Would you rather know in advance? Would you end your pregnancy? Would you continue and not care either way.... think about what you would do with a confirmed diagnosis.

Everything I own, no. But I'd be buying a ticket (which I normally).

Personally, I wanted my calculated risk to be lower than my age based risk. I wouldn't be worried, the odds are actually okay, but I'd want the nipt. Also I could afford to make that decision which I appreciate some can't.

You are all totally right when you ask how this would affect me and I really don’t know. I’m the breadwinner in a stressful
role and I worry that a disabled child would suffer more with not having me around as much. I’m sure my fiancé would do all he can but he will still also still need to work. I’m worried that childcare options would be limited but also sure that we can overcome this somehow.

it’s not that precisely 1 in 495 babies will have DS, this is a “best prediction” based on your results. The number can be higher or lower.

I’ve read somewhere on nhs sometime back when I was researching for my first pregnancy that something like 15% of DS cases are missed bc W get a low risk result at the combined test.

And most of these W (like 80%) are young, under 35. That’s bc most older W will get a higher risk (based on age and or bc the results are less likely to be optimal even if the baby is healthy and has no genetic abnormalities, again bc of age).

So these older W will be referred for further tests like nipt or amnio and DS cases are more likely to be caught for them rather than for younger W.

now your result is ok, your chance of having a baby with DS very very small, so it’s down to you.

I would do the nipt/harmony test bc it would be too much stress for me. And if I can mitigate any risks, I will. nipt is noninvasive, 0% chance of miscarriage and extremely accurate, though only cvs and amnio are diagnosis tests. It’s expensive so that’s a consideration.

if nipt would have came back high risk only then I would have gone for one of the diagnoses tests.

I had my 20 week scan just before xmas n found out the nuchal fold is higher than normal range im 36 will be 37yo when baby due. Ive when really worried about this and awaiting further check on 5th but think i should get the harmony/iona or other testing any advice much appreciated

@Fmlgirl Hi, mine has come back similar as 1 in 484. I'm 36. What did you decide to do?

Hi i had a repeat scan done and they said that the measurement was now within normal range. If it had been high again think id go for that blood test to be sure just so i knew what i can expect. Theres no guarantee with these things i guess but now im 25 weeks im bonded and already in love. All the best with deciding what to do x

@Butterflies12 decided to do nothing and just put it to one side. Figuring my age and BMI must be a big factor. I got my 20 week anomaly scan this week so will see how that goes.

All the best x