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Inaccurate high risk NT scan -any similar experiences?(49 Posts)
I recently had the combined test on the NHS and was given a 1 in 40 high risk rate of Downs. My husband and I were devastated. We talked our options through with the specialist mid wife. She explained that we could go for a CVS or amnio, but both procedures had a risk of miscarriage. We asked if we could be re-scanned by a Consultant (our sonographer had struggled to get a measurement) and we were told this wasn't an option.
In the end we decided to pay for the combined test to be re-done at the Fetal Medicine Centre in London by the Prof who pioneered the test originally & was recommended to us as the leading UK expert (cost of £180). We are so thankful we did this. Our nuchal measurement was checked and rechecked multiple times (our NHS sonographer took only 1 measurement after struggling to get a measurement at all) and the most they got was 2.2 compared to the NHS 2.9. They also looked at multiple soft markers including the nasal bone, flow of the heart, flow of the liver etc... and lowered our risk to 1 in 9072!
Both my husband and I are now feeling quite cross that the NHS would have proceeded with CVS or amnio without re-checking the nuchal.. We recognise that nuchal measurements can flux but 2.9 to 2.2 strongly points to a human error. If we hadn't gone to the Fetal Medicine Unit then we could have proceeded with an unnecessary invasive procedure putting our pregnancy at risk.
We're thinking about challenging our hospital's decision not to offer a re-scan as we'd hate other parents to go through an unnecessary CVS/amnio. We know the NHS can't offer the more sophisticated soft marker assessment but we do think they should offer to re-check the nuchal measurement. Before we raise our concerns I just wanted to check if anyone has had a similar experience or has any comment?
How many dates elapsed between the NHS & private nuchal scans?
I think you'll find the fine print covers the error margins in NHS scans. So you will be on a hiding to nothing.
Thanks for your post :-) There was 1 week between the NHS test & the Fetal Medicine Centre test. After reading your post I had a look through the small print. They do emphasise this is a screening test not a diagnostic test that gives a risk factor not a diagnosis of Downs. However I couldn't find any info about quality assurance for the risk factor given. In otherwords what gaurantee you have that the component open to human error (the scan measurement) is correct in a high risk case without it being re-checked. Any further thoughts are much appreciated.
I've had 2 12 week nuchal scans with dc1&2. Both times (NHS) I've had the nuchal fold measured at least 5 times and the highest measurement taken.
Tbh I think you we're unlucky. I would probably write to the manager of the ultrasound department or PALS and explain what happened and how upset it has made you. I think it would have been reasonable for the sonographer to have asked for a second opinion at the time of scanning as she had such difficulty. Personally I would word this as something to learn from rather than a complaint, as having a week between scans and bloods, you can't really compare the 2, though of course your nuchal should have gone up not down with the increase in gestation.
At the moment you understandably feel angry about the stress you were put under. Try to let it go a bit for the sake of your pregnancy.
I also went to Fetal Medicine Centre for an early scan, I can't recommend them enough.
As far as I was aware your risk is calculated using a combination of scan measurements and blood test. Hence we knew our measurements when we had the scan but had to then go for blood test and wait for the combined result.
Did the Fetal Medicine Centre also check your bloods?
HPSauce - thanks for your response. You're right... at the moment both me and my husband are feeling quite angry that the NHS put us through so much unnecessary stress. It was really awful having to decide whether or not to have an invasive test that could have caused a healthy baby to mis-carry. What you said is very sensible. It's probably best for us to wait a few days, let the emotion subside and then frame this more as a constructive comment. Hopefully that way there might be more chance of it being taken onboard as feedback :-)
Christelle - thanks for your question. Yes they also took our bloods and the results from both the NHS and also the Fetal Medicine Centre were broadly the same. It was the difference in the Nuchal Scan plus the Fetal Medicine Centre's assessment of soft indiciators that bought the risk down to such a lower figure.
Photographerlady - I couldn't agree with you more. They were fantastic. I wish I was based in London and covered by Kings Hospital so I could access the team through the NHS. They're all incredible and amazingly skilled.
I believe they are also one of the few places in the country that can do the harmony test. As fa as I could understand, it is a non invasive diagnostic test that uses genetic sequencing on mothers blood to test for Downs. I have looked into this. And if, touch wood, I got a high risk result from the NHS, I will be getting the harmony test on private, and avoid the CVS and amnio.
I'm not London based either, btw. I wish the harmony tests are more available.
Onelittletoddleterror - I'll be keeping my fingers crossed that you don't get a high risk result. If you do there's a good link that lists all the places that are currently offering it in the UK (you just need to scroll to the bottom)
Best of luck!
Thank you hovis for the link. London is still closest for me, but I didn't know there are three choices.
You are talking about a difference of less than 1mm.
While I appreciate that you must have been anxious, your first NT measurement was normal and not hugely different from the second.
Margin of error is around 0.4mm, so your first measurement suggests that the actual NT was 2.9+/-0.4mm so 2.5-3.3mm. The second scan was 2.2+/-0.4mm so 1.8-2.6mm. It doesn't suggest human error to me but that your risk has changed because of the slightly smaller measurement and the other soft markers.
Similar happened to me. I was measured at 4.6 and given the scary odds. I was booked in for a CVS 2 days later. However, before they performed the procedure, they rescanned and it was only 2.6.
It was put down to human error of the first (senior) sonographer as the Dr said the result couldn't alter so much in 2 days. The first sonographer also hadn't included any photos so they couldn't check what she was measuring.
I thought they always rescanned before an amino or Cvs though?
I also wonder if you had your scan done in the same east London/Essex hospital as me.
I agree with Bartlett it's a difference of 1mm or so, taking into account margin for error. The nhs don't check for soft markers, not sure why but I'm guessing this may change in the future as more evidence and research becomes available. Nuchal testing wasn't even offered on nhs for my first 3 pregnancies, just the triple test bloods at 16 weeks. Tests on offer are better now on the nhs than they ever have been before, but will always lag behind private companies who charge huge amounts of money for the more sophisticated tests they offer.
Bartlet/Thinkingof4 - thanks 4 the info about the margin of error. When we got our 2.9 measurement we were told it had a MoM score of 1.95 (double the average). So when our MoM score dropped significantly with the new NT measurement we assumed that was the main reason for the shift in risk. As you both say it may well be down to the soft markers.
Hazbo - thanks for sharing your experience. The midwife from the hospital called today to ask about the private results. She also thought it seemed quite a shift. I double checked about the policy on re-scanning. She explained that if they re-scanned it'd mean you could have 2 results & be non the wiser about which one to trust. Hopefully if we'd gone doen the CVS or Amnio route they would have re-checkef just before? FYI -my NHS scan was at the John Radcliffe in Oxford. I hope things turned out alright for you after the re-scan.
Did you have the harmony test done?
In the end we decided not too as the odds were so much lower after the more detailed scan. However if we'd got another high risk then we would have done. My husband and I had both decided that if we had a Downs baby we'd keep it. But my husband wanted to know in advance so he could mentally prepare himself. Having become a google fiend these past few days the Harmony Test keeps coming up as a fantastic non-invasive option.
I think you are being unreasonably unfair on the nhs. First of all the nt measurement alters over time and with baby's growth. . Just because the second measurement was lower does not mean it was more accurate. I actually think it is irresponsible to remeasure. You basically got answer you didn't want and wanted a second test to give you A More preferable answer. Don't have the test if you don't want a difficult answer.
Mine went from 4.6 to 2.85 6 days later. It can go down if the fluid reduces, so maybe it just went down..? They cold both have been accurate measurements a that point in time. My consultant was equally happy that the fluid could have and had reduced to that extent in the timeframe.
The only thing I would be annoyed about is no rescan, but when I had an amino they scanned me first anyway, they could have measured then and you could have refused the needle.
I had the CVS the other day and my test came back clear ..phew....but I have to say although it was stressful it was not bad. Everyone has a 1 in 100 chance of miscarriage anyway. I'm not saying do it but I i believe I was treated well and the risks when taken in to context are not any higher than usual. I hope no one has to do the test but don't be scared if you do. The NHS give you the worst case scenario for everything to cover their backs and it is all good advice but on careful thought it is not that higher risk. I do hope however the new test comes in soon with just blood test and not a 7 inch needle!! LOL
I agree with Bodicea (up to a point). Even though you've had a horrific scare I do think you're being a bit harsh on the sonographer. These specialists undergo rigourous training, but they are HUMAN and sometimes mistakes can happen. Also - the NHS is FREE (as in we don't pay upfront) and we (ask for and) get a lot for our taxes. Everytime I've gone for a scan there's a huge backlog, massive overrunning times and a long wait. I will not blame the staff as they do a tremendous job under arduous circumstances and even thought the sonographer seeing me is working under pressure, aware of the queues etc they've always tried their best to a) scan my baby as efficiently and accurately as possible and b) reassure me and let me know what's going on.
I'm sorry you had a tough time, but please don't take it out on the staff...
It just goes to show what a load of bollocks the combined test is. At no other point would anyone accept a test with a 1 in 20 false positive and failure to pick up what it is meant to 25% of the time. It amazes me that people have it tbh.
Thanks to everyone for their reflections. I've learnt so much from these posts about the Combined Test which i didn't previously know. In the end we've decided not to raise a complaint, but we are planning to share some general feedback. I agree the NHS offer a fantastic service for free & the staff work tirelessly often for limited pay. I hope our feedback will be seen as constructive not critical:
1.) As was previously said there is always going to be an element of human error. That's just life. But I wonder if it'd help if a minimum number of pictures (e.g. 3) had to be taken of the NTT for the test to be valid?
2.) When we were discussing our options we felt like there were only 2 on the table. Have an invasive test or wait to know the outcome when the baby's born. Reading sites like Mums Net I learnt about the Harmony Test and the more detailed soft marker scan. I'm conscious the NHS can't offer these services, but I wonder if they could mention them when going through the options?
3.) When I signed up for the combined test I knew it was a screening test. But I had no idea about the high false positive rate. If I'd known that we probably wouldn't have gone for the test. It would be really helpful if the NHS could include thess stats in the booklet they give out to help inform the choices people make.
Thanks again to everyone for their comments :-) The whole experience has been quite an eye opener!
The NHS booklet is really clear that these tests are screening tests and can not pick up every baby with problems or guarantee a normal result for your baby.
Part of the problem is that people (going for a sweeping generalisation here) don't understand statistics so false positives or negatives or sensitivity/specificity of tests would mean very little to people. You see here on MN all the time people rubbishing studies because it isn't true for them ("That study is nonsense. My son was BF and has eczema so it can't possibly be protective.") or misunderstanding the risks of things like the NT ("I've been given a risk of Down's of 1:100. Has anyone had a similar one and had a good result?"
brettgirl said, "It just goes to show what a load of bollocks the combined test is. At no other point would anyone accept a test with a 1 in 20 false positive and failure to pick up what it is meant to 25% of the time. It amazes me that people have it tbh."
Her statement isn't true at all! How many of us would decline breast screening? It has a false positive rate of 80% if you look at the statistics of what the outcome is of women who are called back for further testing!
Bartlett there has been quite a lot of discussion about breast screening as well. Totally off topic but that also has arguably harmful net effect from women having unnecessary intervention. My mother thought very long and hard about whether or not to have it.
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