NT testing(17 Posts)
Hello - I'm having NT testing in the next few weeks and was wondering if anyone could help me with the answers to these questions before I go:
- is chromosomal abnormality likelihood indicated by high/low or are we given numbers, e.g. 1:100?
- what is considered high? I thought I'd read somewhere than 1:140 was the "high" threshold, but aged 40 the general risk is 1:100, so would a "normal" risk level at that age prompt them to offer amnio etc?
- what are the "normal" ranges for HCG and papp-a protein? (Just so I can understand the results) - will they offer the exact numbers?
- is it possible that a chromosomal abnormality can be picked up by the test, despite there being no soft markers during the scan?
- what does the harmony test measure that is different to the NT test? Is it worth having the harmony test before NT results come back? How much more reliable are harmony tests than NT tests?
Sorry for all the questions, I'm just trying to get my head around it all.
You will be given the number
At most hospitals if it is 1-150 or higher you will be offered a diagnostic test (CVS/Amino)
They will give you the MoM numbers from your bloods
Most NHS NT scans don't look for soft markers - they measure the nuchal fold
Harmony is looking for fetal DNA in your blood. It is more accurate but it is still not diagnostic
Hi. I agree with the PP about the NT test.
Personally though, from the point of view of someone who's baby was diagnosed antenatal lying with DS, if you would want a definite diagnosis, I wouldn't bother with Harmony.
It will still only give you a risk factor. There was a very sad thread on here a while back by a woman who's harmony came back 'negative' but who had DS diagnosed later in PG.
IF you would require a specific diagnosis Harmony just delays the inevitable. The only way you will get a confirmed diagnosis is by CVS or amnio.
Thanks. To be honest, I'm less worried about DS but more about t18 and t13, which aren't compatible with life.
I'm serious considering not having it, but I'm not sure I can explain why.
Harmony is very sensitive for T21, a bit less for T13 and T18. For T21, the sensitivity of Harmony is over 99%, whilst NT+bloods ~ 85% (it is also age dependent for NT+bloods, it is less sensitive for younger women). So yes, the chromosome abnormality may be missed by Harmony as well, and there was a sad thread here about it, but MUCH LESS frequently than by combined screening.
In my opinion, it is worth having both, as Harmony is more accurate for trisomies, but it only tests for trisomies, whilst combined screening less sensitive for trisomies, but can also pinpoint to other issues (problems with placenta and some other abnormalities).
However, it a very personal decision, and I understand that some women decline any testing for variety of reasons.
Wishing you the best whatever you decide!
Not having the NT measurement taken OP or not having the scan at all? I don't know if you know, but if you have the scan, but opt out of the measurement, and the sonographer spots anything anomalous, they HAVE to tell you. So even if you decide you don't want the testing you could well still leave knowing that something was amiss.
I would have the measurement taken in the scan, but possibly opt out of the blood test. I just can't decide.
I'm pretty sure I don't want invasive testing, so am wondering why I'm subjecting myself to the almost inevitable worry...
The bloods will have a different pattern for T21 vs T13/T18
My dd2 had t18. My 12 week bloods looked odd but the risk assessment gave us a lower (as in much less chance) than 1:100 and therefore it wasn't reported.
The soft markers were picked up at 20week anomaly scan.
As someone who had a tfmr at 22 weeks I would say have the scan and bloods, request that they also report t13 and t18 blood risks (many trusts don't unless you are high risk)
I reckon you'd rather know before 21 weeks, if you did decide on a tfmr the procedure is a it more grim after 21 weeks as you need an injection to stop the baby's heart. This was easily the worst part of the process. Under 21 weeks you can be induced and give birth without the injection (the baby will not survive labour) and before 16 weeks (I think) you can have a surgical termination.
Sorry for the grim post but I think it's important to have all the facts. You may say that you wouldn't have a termination anyway, that is totally your choice. I would say you may not know how you feel until you get those results.
Please remember that the risk of t13 and t18 is around 1:8000 baseline. You hear about them because they are devastating but they are also fairly uncommon so please don't overly worry about them.
Thanks kitty that's really helpful. I'm sorry for what you went through.
I don't think I said I wouldn't have a termination for medical reasons, I think that would be something I'd consider for t18 and t13, but not necessarily for t21. Unfortunately I've given birth at 22w before and the thought of going through that again horrifies me...
Normally I'm a person who likes to have all the facts, but as this is probably my last pregnancy and I've had a number of losses, I think I just want to stick my head in the sand.
ItsCurtains, my DD has DS. I would not have TFMR at any point and I wouldn't if I became PG again, BUT, I did have all the tests including CVS because I wanted to know in advance what we were facing.
And honestly and truly it was absolutely the best thing for us. Once we knew for definite, We passed through the 'greiving' period for our 'perfect' baby, and got our heads round the future. We told everyone. I joined support groups and made new friends. By the time she was born everything was fine. There was no breaking the news to people, no shock, we were prepared.
And I would totally do that again. And recommend it.
I would not want to have found out at birth. its a very hormonal, emotional and stressful time anyway.
Sorry curtains I don't think I worded my last post properly. What I meant is you might 'feel' that you don't want a tfmr when you find out (rather than say you don't, say wasn't the right word!)
I'm sorry you have already suffered a loss. 22 weeks is awful because it's so far gone. I only mentioned the 22 weeks in relation to the options changing after 21 weeks in terms of termination procedures.
What I meant by my comments is that if you get bad test results you may feel you don't want a termination anyway. I have a friend who carried to term her son with t13. Termination was our option, it's often assumed that's the route people will take but what I was trying to say (in not an effective way!) was don't feel pressured into either route.
I'm really sorry if my post came over wrong or wasn't helpful. It wasn't intended that way. The last thing I want to do is make you feel worse
Again I'm sorry
Kitty there's no need to apologise, I really do appreciate your input. I'm really hoping all this advanced worry is for nothing!
At least I might have a better idea after the nuchal measurements are taken next week.
I'm sure it is. It's a horrible time but you are more likely to get a negative screen than positive.
Hopefully you'll have so,e good news soon and this will just be an awful memory
Just to update. I had my scan today, NT measurement of 1.5, which I was pleased with.
As my appointment afterwards was with the consultant (who I'm seeing for recurrent miscarriage and other additional complications) we all forgot about having the bloods done. I'm almost relieved that the test/no test decision was taken out of my hands, although I appreciate that this isn't the right choice for everyone.
I've decided that I'm going to live with knowing the NT measurement is OK and take everything as it comes. I have another scan booked for next week then another two weeks after this, so I know they'll be monitoring me for any abnormalities via that means.
Thanks for all your support.
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