Does anyone know anything about the screening tests that are done for Down's Syndrome etc? I have just been told my risk is 1:70 and I have some questions...

[OneInSeventy]

Hi, I'm a bit of a regular but am in disguise as I have only spoken to DH about this in RL and would like to stay incognito for now.

I wish I had never had the test done - in hindsight I'd rather not know - but what's done is done and I have to decide what to do next (if anything). The result is from a blood test only, nuchal fold scans aren't offered in my area. I'm 17 weeks pregnant.

I understand that this risk equates to around 1.3% which really isn't much at all, but I need to think this through properly and consider all my options.

I have an appointment on Wednesday morning and will be asking all my questions there, but if anyone has any info I'd be grateful for your input.

So my questions:

I understand that the risk of DS increases significantly once the mother reaches 35. I take it that the mother's age is used when determining the risk, but is there a sliding scale that's applied as you get older or do they just apply a one-off risk factor once you reach 35? I ask because I turned 35 in Feb, I was 34 when this baby was conceived but 35 when the blood was taken. I wonder if the blood had been taken from a 34 year old, would the risk automatically be lower?

I've already been offered an amnio, which I probably won't accept (risk of MC too high for me, also a positive dx of DS probably wouldn't alter my wish to continue with the pregnancy). From what I have read, it is possible to determine risk factors with a scan, should I press for a scan instead of an amnio? I have my anomaly scan booked for just over 3 weeks' time anyway.

I've been taking stemetil for HG - could this have skewed the result or increased my risk factor?

I'm sure there will be more questions but tbh my head is spinning a bit.

TIA

bump, boards moving quickly tonight

I'm bumping for you too, my sister went through this but I can't remember the tests etc she had done.

If you don't want an amnio, and don't feel you will do anything, I am puzzled as to why you are carrying on with tests?

I don't think 34/35 makes much difference, but blood test alone isn't very reliable - could be many reasons for a higher result.

I had a triple test (including nuchal scan) and planned, if the result was classed high-risk to opt for an anomaly scan rather than an amnio (we don't get a routine 20wk scan here). My result was low risk so testing ended there, but I would have wanted the scan so that I could be aware of any heart defects - the scan couldn't really have been much more predictive of a chromosomal anomaly as soft markers are no more diagnostic really than the blood tests.

I had nuchal and combined bloods so slightly different but they took my actual age into account - so am 36 rather than just saying 35+.

They'll look for soft markers at the anomoly scan but am not sure how conclusive an answer you'll get without having an amnio.

I do understand though that you'd like to know one way or another to prepare yourselves.

Good luck.

Oh - have you had any bleeding at all as i know that makes the blood tests even more unreliable.

Here's a table of risk based on maternal age.

You're right, in any other scenario 1.3% would seem low risk.

Sorry, here

We declined the nuchal because we knew when they tapped my age (41) into the computer the lights would start flashing...

You could have a private scan I suppose, if you want to know the nuchal fold measurement. It costs about £150 i think.

I do understand what you mean when you say the test is done now and you have to deal with the results, but as your risk (just 1.3%) is already low (I've had friends who were 1 in 6 and their babies were fine) if you can make a decision about whether or not you'd go ahead with the invasive testing (or ultimately the pg), then you'll have your decision on what to do next.

We felt if we were going to get any bad news we'd rather get it with a baby in our arms.

1.3% sounds pretty brilliant to me! This blasted test seems to bring about much more angst than clarity!

Onein, sorry, don't know if any of the above will help you, wishing you all the best,

And of course in nature, nothing goes up or down significantly at any age, only statistics can do that!

Thanks so much everyone. I did mean to come back to the thread last night but dh and I talked until late so I went to bed.

MuffinBaker - we just want to be armed with as many facts as we can gather. If we have a scan and it shows no obvious problems (excellent point made by Shonaspurtle about heart defects) then we will be able to relax a bit. If there are problems, we then have the option to change our minds about the amnio.

Traceybath - no bleeding in early pregnancy.

THanks for the link Shonaspurtle, that was interesting.

A nuchal scan would be useful but I'm not sure that at 17 weeks we haven't left it too late. Does anyone know?

17 weeks is way too late for nuchal.
I think best way forward, from what you've said, is see what the 20 wk scan finds. Decide about amnio after that.

The big drawback is if that scan reveals big problems, and then you went for amnio, you have to wait that much longer to be sure things are likely to be ok.

Good luck

Oneinseventy, was it the 'triple test' you had? If so, the false positve rate is notorious, and for this reason has been abandoned in some health authorities (out of 100 women having bloods taken, 20 will get a 'high risk' result; of those 20 only 1 or 2 will have an 'affected' baby). The odds are very much in your favour!