Could the initial CVS results be wrong?

[SmallMexicanChihuahua]

I was just told that my CVS results are positive for T21. They said there were no signs of mosaicism so they consider this diagnostic.

Unfortunately we would terminate with this diagnosis, however I'm really scared that it might be wrong. I think I read something about a case in Ireland where they terminated based on the initial CVS results but then the full results were clear. I phoned ARC and they said some women have an amnio to know for sure but obviously that prolongs everything.

Has anyone been through something similar where the CVS was wrong and you had amnio to confirm?

I guess I'm still in denial and should just accept it. The combined screening results were very bad with NT of 4.1 and HCG was almost 8. But then at the CVS ultrasound NT had dropped to 2.7 and structurally everything looked fine so that gave us some hope.

Hi

Firstly I'm sorry you're going through this stress and worry, it's awful.

I had a NT of 8mm, and was asked to come back two days later for a consultant to check before I was referred to fetal medicine. At that consultant appt I asked if the measurement changed and he said they wouldn't measure it again, the fact that it was high at the first scan was enough. I also asked if they could see the nasal bone but they said that's not something they check in our area.

I'm not medical, but I have read that the NT measurement can only be taken between 11 weeks and 13 weeks 6 days - after that, the tissue gets thicker and is no longer translucent, so test results become inconclusive. This could explain why the measurement has gone down.

I'm afraid I don't have experience of the CVS, we didn't get to that stage, the prognosis was too poor at the scan and the NIPT came back high risk for Edwards. I just couldn't be stuck in limbo any longer and having a CVS would have meant another week or so waiting on results.

If you feel any doubt, I think it would be reasonable to ask for an amnio.

I am really, really sorry that this has happened to you. The chances of the CVS being inaccurate is incredibly low, and only really "wrong" in the rare case that the trisomy is exclusively in the placenta and not in the foetus, or another kind of mosaic. But combined with the NT and hCG, you already have a definitive answer, they are telling you that these three things together aren't going to be anything else. You just don't want to believe it, which is completely understandable. You didn't say how many weeks you are, but I think waiting long enough for an amnio might make termination more traumatic.

I had already decided I would terminate if I got indications of a trisomy, but I hadn't told anyone of how I felt. And quite by accident I learned that lots of people have the opposite attitude - so I decided then & there that if I needed to terminate I would use the line that "baby just didn't make it" to avoid the judgemental attitudes. You're the only one who gets to make the decision so protect yourself from do-gooders who'd make you feel bad about whatever you decide.

So very sorry to hear this. I do have a story where amnio contradicted the cvs on t21 but they say this is super rare. I also haven’t had the baby yet, am 29 weeks today, so still hoping all is ok although they are pretty optimistic.
I had hcg of 7.7 and low Papp a, however nt was 1.3 and there was never anything abnormal picked up on the scans. I had more than 1 in 2 chance on the screen, high chance nipt and then cvs quick result abnormal. However they told me at the time they couldn’t exclude confined placental mosaicism (not sure what it was in the results that led them to say this vs the response they gave to you) and then I had an amnio which shocked all the medical staff when it came back normal as they had told me chances were tiny. The karyotype for the amnio and the cvs were also normal. Are they going to do the full karyotype on the cvs? I was always going to have the amnio but it really depends how long you have to wait I guess. I really feel for you - the waiting is absolute hell. I don’t want to get your hopes up because they do keep telling me how unusual it is, but I do see why you might want the amnio to know for sure. Feel free to message me if you want to talk more x

I had a 99% chance t21 on nipt test , anaploidy detected .
Waited for cvs to confirm , which it did, and told it was not mosaicism . At that point I decided not to go ahead although it was an extremely difficult decision.

I think it is an accurate test or at least was in my case and decided not to wait further for amnio, ,my situation was further complicated my then partner being extremely unsupportive of the pregnancy anyway so that tipped it for me .

(We separated after anyway )

In hindsight , it was the right thing as I was mid 40s and would have been a single parent with no support network had I continued with the pregnancy,

I'm very sorry you have got this result .
Arc were very helpful.

Thank you so much everyone for your kind replies.

@MrsScotland , I am so sorry for your loss, it's heartbreaking. Thank you for explaining about NT, I'd read somewhere that they don't measure it after 14 weeks but couldn't understand why. I was 14+5 the day of the scan so that makes sense.

@Froooty I think you're right, I am in denial. I'm terrified that there's a tiny chance that we might terminate a healthy baby and I could never forgive myself for that. But if I do the amnio that adds at least another week and I'm already 15+5 and getting attached to the baby.

@CB1209 That sounds crazy, I'm so happy for you and hope everything turns out OK!! You are so resilient going through all the different tests, having been given such a high risk as well, that must have been really hard. I'm not sure about the mosaicism, they told me at my appointment that they can tell whether it might be that but didn't say with how much certainty. Also said it was very rare. They are doing the full karyotype but that would be another two weeks and she didn't give me any hope that the result might be different. Your story does give me a tiny bit of hope though as I'd only found similar cases with T18&T13; it looks like both cvs and nipt are more accurate for Down's.

@capabilityfrowns I'm so sorry this happened to you and that your ex was a coward who wouldn't support you at such a vulnerable and frightening time. Did they tell you after the quick cvs results that there's no mosaicism or did they do the full ones?

I'm sorry OP. Did you also have an NIPT in addition to the CVS? Did they check for the for the nasal bone during the scans, or offer a more detailed scan? I'm glad you have been in touch with ARC, because I was going to suggest them too.
I paid for the NIPT at 11 weeks and it came back as T13, patau syndrome. They gave me a more detailed scan which showed NT 6.5mm and multiple issues on the scan. I was offered both amnio and CVS, but due to the other results and discussing with the consultant, I chose TFMR. I also didn't want to wait additional weeks. The autopsy/histology confirmed the diagnosis.
I'm happy to answer any questions you have. Just remember that this isn't your fault and you aren't alone going through this

Hi again op

They told me the initial findings after 48 hours and then confirmed them after the full results came back .

It was only at that point I decided on a tfmr .

@SM4713 Thank you for your kind words and I'm so sorry you've been through this too.

I haven't had NIPT but did have a detailed scan as part of the CVS. Everything looked structurally normal, nasal bone was there (baby seems to have my big nose!), even the NT had dropped to normal levels. The consultant and the sonographer were very positive. That's why it's so hard to accept the diagnosis and I keep thinking that there must be some mistake, although I do realise that Down syndrome doesn't necessarily show on the scan as much as Edwards or Patau.

My cvs said my son was absolutely fine and he isn't so I'd say it's unlikely to be wrong in your favour .

If the bloods are off they are off for a reason . Not all genetic conditions are detectable in utero .

Thanks @capabilityfrowns. Did they give you any hope that the final results might be different?

I was told that my baby definitely has Down's as there was no mosaicism in my placenta so there's no point in waiting for the full results.

i guess what you need to decide is if you don’t have the amnio will you always wonder.. and then if so is removing that question worth waiting another week for results? This is by no means me diminishing how horrific the limbo is, I vividly remember saying I can’t carry on like this for weeks when they started talking about full karyotypes taking weeks. If they do get you in for an Amnio is there anyway they could do it as soon as you hit 16 weeks and then you’re almost there? I think they did mine at 15+6 in the end. Got the result at 16+5, but that was also because the weekend got in the way. Just my thoughts, everyone is different of course! Good luck x

Ladies, could you please help me understand this sentence:

Mosaicism and/or segment imbalance for the chromosomes tested may not be detected.

It says this in bold at the bottom of my test results and after some white space so it doesn't look like part of the results.

To me it sounds like, if there is mosaicism then it is possible that the test may not detect it. But then English is not my first language, and I'm probably clutching at straws at this point.

My DP is British and at first he said it meant that there was no mosaicism in my sample, which is what they keep telling me. But then he said it was worded in an unusual way and it's not clear what they're saying.

I think it would be best if you rang the department who did the cvs at the hospital and ask definitively what they're are saying that way you know for sure .

I asked all the same questions. And it's hard to take in when you're in shock . But the experts are the best people to ask so there is no misinterpretation of the results .

Xx

Thanks capability, I'm supposed to be getting a call from a consultant tomorrow so hopefully they can explain.

This morning I was going to try to book a private amnio for next week just to give us some certainty. I don't think the NHS will give us an amnio and even if they do, our cvs referral took ages, and I want to know asap. However, we had a call with our screening midwife and she really discouraged us from getting an amnio. She kept saying that the cvs is diagnostic, there is no mosaicism in my placenta, and my baby has Down's.

I was mentally preparing myself to go ahead with the termination early next week, then I saw that sentence at the end of my results. Now I'm kicking myself for not booking an amnio this morning. I just keep thinking that the cvs is not 100% accurate, and while it's extremely unlikely that it was wrong in my case, I can't abort my very much wanted baby on a basis of likelihood.

I'm so so sorry you are going through this, it's the most awful thing ever. I had a similar situation over summer and chose to terminate based upon CVS only (didn't even consider mosaicism or waiting for an amino). Mosacism was never discussed (I just read about it online after), nor was the option of an amino, it was as if CVS was a definite diagnosis and this was a leading fetal medicine unit.

I think if you decide you go ahead with termination, you can be 99.99% sure that the diagnosis was correct. (I too didn't have any markers on the scan and the NT reduced by the date of CVS). I don't have regrets about the choice I made, despite it being the worst time of my life. I am now pregnant again (11 weeks) and nuchal scan this week was fine and I came back 1 in 2500 risk, compared to 1 in 2 last time. It would be very unlikely to happen again if you get pregnant again.

Sending so much love. xx

Hi op
How did the call go ? Been thinking of you . X

@User69611 @capabilityfrowns Thank you for caring xx

User, I'm sorry you had to go through this too but so happy for you now. I hope you have an amazing, problem-free pregnancy that you can totally enjoy!

I did think about just going ahead with the termination to get it over with ASAP. Kept swinging between that and doing an amnio first. But after discussing with my partner he prefers the amnio option and I think I do too. Not because I believe that my baby doesn't have Down's, but I think I'd be much more at peace with my decision if I know that I've done everything to make sure that the diagnosis is correct. I also have a nasty chest infection right now so can't imagine going through a termination in this state, I get exhausted just climbing the stairs.

I spoke to a lovely lady from ARC this morning (Jane) and she was very supportive and said that it sounds like the right decision for me is to wait either for the amnio or the full karyotype. She told me that it wouldn't make much difference whether I give birth at 16 or 18 weeks. She also gave me way more info about mosaicism and results than any of the medical professionals I've encountered have bothered to do.

This is what really annoys me and maybe that's why I've been so stubborn about the amnio. It would have made a big difference if they'd said something like "This test is known to be 99.8% accurate. Considering all your other results we conclude that your baby definitely has T21. You can go ahead and pay for an amnio if it will make you feel better but the result will be the same." Instead they just keep repeating, "The test is diagnostic, your baby has Down's". When I ask how accurate is the test, is it possible that it could miss mosaicism, it's again "it's a diagnostic test". I'm sure I heard it the first 50 times, there's no need.

I didn't get a call from a consultant today, instead the screening midwife called to say she's talked to the consultant and they agreed with her that there's no need for further testing. She asked if I still wanted the consultant to call me - yes please. She spent some more time telling me how much worse it would be to terminate later and how it would carry "greater risks for the mother". When I asked what risks the answer was "well... you know... general risks". I waited to hear more and there was an uncomfortable pause.

I managed to book a private amnio for next Tuesday and hopefully I'll have the results by the end of the week. So I can start the termination process the week after and that would only be a couple of weeks delay.

Sorry this was long!

Bless you sweetheart but yes you need to do what's right for you and be sure .

I don't think there's much difference in the process after 12 weeks to be honest , it's hard , it's the same process . Take the pills , the pessaries , and go through "medical management " , but you need to be sure you are doing what's right for you .

I'll be thinking g if you and hold you in my thoughts . Xxx

I’m so sorry you’ve had such a tough experience with the midwife - exactly what you don’t need when things are unbelievably hard. From what you’ve said I definitely think it sounds like you need the amnio to help deal with whatever comes next. Am so sorry you’re going through all this x

@SmallMexicanChihuahua that definitely sounds like the right decision. So sorry you have had such awful midwife and consultant (or lack thereof) experience- makes the whole thing so much harder. I’m sure there are no further risks with termination waiting another week, I had a surgical one rather than medical but can’t see how it would be more risky a week later.
anyway, hope you feel better soon with chest infection and hold up ok the next few weeks, and maybe a miracle outcome like @CB1209 . Take care and keep us posted xx

I'm so sorry you're going through this OP and anyone else.

Hi @SmallMexicanChihuahua I’m so sorry you’re going through this. I am in the same situation. At 11 weeks we had a scan and our baby had an NT of 3.52 so the doc advised an NIPT. Had an NIPT test done last week and it came back positive for T21 on Tuesday. We are devastated but holding on to the tiny shred of hope that potential placental mosaicism gives. I’m now 12.5 weeks and had a scan on Thursday (30 Nov) The NT was between 2.5 and 2.8 (reduced) and heart brain nose all looks fine.

We originally considered CVS as a diagnostic but due to my recent healthy scan we wouldn’t feel comfortable making a decision based on the rapid results. Full results would be available week 16 whereas the amino can be conducted week 15 fingers crossed, and the results would be definite. Also as it will check our baby instead of the placenta we feel like it will give us more peace of mind so we’re opting for that.

Waiting for the amnio to come around is hell though, especially on the run up to Christmas. Trying to stay focused at work is equally challenging but at the same time I know I need the distraction.

Sending love and hugs to anyone who is experiencing this, I wouldn’t wish it on anyone. It’s an impossible situation. Please reach out if you need to talk as it’s a very lonely place to be. xx

How are you doing OP?

Hope you're as ok as you can be @SmallMexicanChihuahua

@Cait2023 I'm so sorry you're going through the same. I hope your NIPT was a false positive; your original NT was basically borderline and your subsequent scan is very encouraging.

It absolutely makes sense in your case to wait for the amnio, but I know it's an awfully long wait and the uncertainty is crushing. For me the waiting and getting the diagnosis was the worst part, I'm 10 days post TFMR and mostly feel numb now.

Sending you lots of love, wishing you strength in the coming weeks and hoping your amnio result is clear xx