Amniocentesis scaremongering/shaming

(32 Posts)
SarahD19 Sat 27-Mar-21 08:53:29

Hello I’ve noticed a few threads on here where people are put off having invasive tests such as amniocentesis or CVS and told to have NIPT.

NIPT is a great screening tool, but it is just that. It has severe limitations that many seem blissfully unaware of (practitioners included). Mainly it has only reasonable accuracy in terms of positively predicting Downs Syndrome (around 80% PPV) - and is extremely inaccurate in terms of detecting any other trisomy in terms of PPV. It is based on Cell Free DNA found in the mother’s blood - which inevitably means some guess work and a level of inaccuracy you would not get as often with invasive tests.

Amniocentesis and CVS also have their limitations. However they actually analyse amniocytes and placental tissue directly, which means more accuracy. Plus an ability to analyse for a whole host of conditions NIPT cannot.

Factor in that miscarriage risk cited much of the time is based on dated literature and technology - the risks seem wildly overstated. obgyn.onlinelibrary.wiley.com/doi/10.1002/uog.20353

It is personal preference what people feel comfortable with, I just felt it was important to say that judging parents to be and guilt -tripping, especially based on misinformation, is unhelpful. No test is perfect, each has there own place in different contexts and for different people.

Rant over!

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LadyWithLapdog Sat 27-Mar-21 08:59:18

I am behind and don’t know what NIPT is. Thank you for starting the thread.

LadyWithLapdog Sat 27-Mar-21 09:01:40

www.nuh.nhs.uk/about-the-nipt-test/ I had read about it but didn’t recognise the acronym.

SarahD19 Sat 27-Mar-21 09:03:49

@LadyWithLapdog it is a non-invasive prenatal blood test. People can have it from 10 weeks pregnant.

It is a more sensitive test than the NHS combined, but also brings up a lot of false positives, particularly if taken within the general population, where it’s PPV is only 37% accurate for Edwards Syndrome for instance. www.asa.org.uk/news/non-invasive-prenatal-testing-nipt-a-look-at-the-asa-s-rulings.html

It is a good screening tool. But it worries me that the statistics are misrepresented still, and the tests can bring about so much anxiety as people do not understand the limitations - and high number of false positives. Some recommend for pretty much every reason going, even gender reveals for instance.

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SarahD19 Sat 27-Mar-21 09:10:40

each test has *their own place (please excuse typos).

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LadyWithLapdog Sat 27-Mar-21 09:14:12

That needs good pre-test counselling and there’s probably not enough time for that in a busy clinic.

SarahD19 Sat 27-Mar-21 09:16:05

@LadyWithLapdog and also where examples like the link you’ve just shared, misrepresenting statistics, need a proper clamp down. But because they are predominantly private clinics, they are rarely held to account. It all seems to be about making money above ethics.

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LadyWithLapdog Sat 27-Mar-21 09:19:14

I didn’t realise it wasn’t accurate. I saw it’s from an NHS hospital. I see their data for eg Edwards syndrome are different to the ones you mentioned.

CovidCorvid Sat 27-Mar-21 09:24:44

In the nhs the NIPT is being used as a screening test. Any nipt which comes back at an increased risk the women will then be offered an amino or cvs to confirm. It isn’t being used instead of an amino.

“ Increased chance

This means that there is an increased chance that your baby is affected by Down’s, Edwards’ or Patau’s Syndromes. All increased chance results should be confirmed by an invasive diagnostic test which could be chorionic villus sampling (CVS) or amniocentesis. Confirmation is required in all increased chance cases as in a very small number of cases the DNA from the placenta may not represent the DNA of your baby”

SarahD19 Sat 27-Mar-21 09:25:30

@LadyWithLapdog it is technically accurate but misleading. Detection rates and sensitivity are interpreted as Positive Predictive Value (PPV).

As I’ve said, the NIPT is very sensitive, but that should not be mistaken as interpreting a positive result with being 91-100% accurate. However this is how the tests are interpreted - by both clinicians and practitioners 🤷‍♀️

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CovidCorvid Sat 27-Mar-21 09:27:04

Personally I haven’t noticed any threads on here where people are being told not to have an amnio but to have a NIPT instead. Hopefully any such person will have it better explained to them by a HCP and can then make an informed decision.

CovidCorvid Sat 27-Mar-21 09:28:27

I certainly need to read up on this more. I’m a midwife, our hospital is going to start offering it soon and I don’t feel I quite understand it.

SarahD19 Sat 27-Mar-21 09:34:27

@CovidCorvid agreed but many people on here do suggest it is equivocal and misinterpret the statistics (as doing so is normalised).

Also many people do not realise there can be obstetric barriers to having CVS or Amniocentesis which can result in weeks, if not months of delays. Even CVS only has 80% PPV in some instances due to a range of issues - and takes 3 weeks to get full results. Many people think “oh if you want to know sex or want a gender reveal, get NIPT at 10 weeks and all sorted. Worst case you could get CVS and everything is rosey”. That is simply over-simplistic and unrealistic.

Yes in the vast majority people will get a negative NIPT result (which has a high level of accuracy) and see the test as reassuring. But for some who have high risk, positive results (which are often not adequately explained) it opens a can of worms that can prove deeply unsettling, traumatic. And even completely unnecessary (arguably more so than an invasive test may do). I think we also need to acknowledge that.

As I’ve said it is a good screening tool, and if used correctly and people are informed, then that is good.

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SarahD19 Sat 27-Mar-21 09:44:35

@CovidCorvid it is a very good screening tool. However I am aware that when people are told it is 91-100% accurate standardly, people default to seeing it as diagnostic/equivocal to amniocentesis.

It can be very good when used within clinical context for Downs Syndrome for instance, where high risk is identified (this sub group is very accurate). However in the general population and when used in isolation, it is far less effective. Many people do not realise this.

There also seems to be a misconception that a negative NIPT at 10 weeks means healthy pregnancy. In fact all it can tell us is there is less likelihood baby is impacted by the main Trisomies. Many do not realise the significance of the anomaly scan and the timing of this - many conditions we do not understand and NIPT has little or no bearing in predicting a range of clinical presentations that may become evident later in pregnancy.

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CovidCorvid Sat 27-Mar-21 10:35:52

Thanks for starting the thread, certainly given me the kick up the bum to do some research.

SarahD19 Sat 27-Mar-21 11:11:22

@CovidCorvid thank you. I know sometimes my concerns are interpreted negatively although I just want better awareness and education.

The NIPT is great in many respects. Each time I hear someone’s tale of how they’ve had a negative result and feel reassured, I am over the moon for each and every one of them.

I just worry looking at some comments. In extreme cases I’ve heard people claim NIPT should replace amniocentesis completely or seen the test as more accurate, even though it is only a screening.

I hear people say “oh you shouldn’t have amniocentesis/CVS due to causing miscarriage. Have NIPT”. I realise a lot of this comes from a good place - but there is misinformation nonetheless.

When people seemingly have perfectly healthy, low risk pregnancies, I have read multiple times people recommend that they should have NIPT to relieve anxiety - but do not explain the limitations/risks... the list goes on.

It is exciting the developments we are making in science, but there is still so much we do not know. In some instances these tests can provide more questions than answers.

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positivebex Thu 08-Apr-21 07:20:38

Just found this thread and find it really interesting especially as I now have experience of cvs.
I was called this week to tell me My bloods had shown I had a high chance of a Down syndrome baby all my other results ie nuchal tests we’re all fine. Unfortunately our hospital doesn’t offer NIPT we would have to seek that out and pay the £400. Me and hubby no matter what we like to know everything and this would have weighed on our mind not knowing so Based on my odds we had 3 choices to either do nothing, have NIPT which would have taken time and a wait for results and if this would come back either low chance or high chance and so still wouldn’t provide us with a definite answer so we still would then have had to have Amnio as I would probably be over 15 weeks at that point. Or our 3rd choice which we took was come back in literally the next day have the cvs and wait 2 days for results and as long as that doesn’t come back inconclusive then we will have a definitive answer one way or the other. This of course has it’s own risks which we weighed up, We didn’t take our decision lightly and many factors played in to our decision, the nurse gave us information on each choice, she had no preference herself on any one and didn’t try and sway us one way or the other, for us cost was one of them since NIPT isn’t offered on nhs at our trust. It was a personal choice and would hate to think people judged us for having the test we deemed most accurate, most timely especially as someone who suffers with anxiety and most cost effective for us, each person/family has totally different reasons for their choices no body should be shamed. I found the cvs daunting, but it didn’t hurt just uncomfortable and we now have 1 day left to wait for the first results which our trust said will take 2 days for first results and 3 weeks for the full diagnostics.

All of this experience has really opened my eyes, and I have to admit I was nieve as in my first pregnancy my 12 weeks tests all come back low probability and I just took that as ah nothing wrong but as the nurse pointed out that doesn’t mean you then won’t have a baby without one of the markers, it just means your probability is lower... and obviously not scare anyone but I feel like this has really opened my eyes on my choices, I have asked myself questions on why I blindly opted for the additional testing anyways at 12 weeks. I just feel much more informed now but it had taken all of that above.

SarahD19 Thu 08-Apr-21 13:24:05

@positivebex I’m glad you’ve found this thread helpful. I think everyone’s circumstances are so unique and what is right for one would not necessarily be right for another. There shouldn’t be judgement either way as long as people are adequately informed and supported. I am glad to hear you’ve had options explained.

My criticism of CVS and amniocentesis is I think the significance of long term cultures are often not fully explained or understood either. On the basis of an experience I had with CVS, I feel that if placed in that situation again, I would go straight for amniocentesis. This is because in my case I had been told that the CVS was positive for Edwards Syndrome and the prognosis was “incompatible with life” to around 99% certainty. It would take the 3 week wait for long term culture for mosaicism to be revealed, which meant a very different prognosis in our case to the rapid results. Then we had to wait because obstetrics meant we couldn’t have amniocentesis until 20 weeks - then that sample got contaminated. So we ended up with months of delays. It is very different to be stuck on that journey for months on end, compared to the simplicity and accuracy boasted on prenatal tests imho...

I have been exactly the same as you in querying if I was blind to opt for the tests at 12 weeks too! I think you generally view it as the tests will provide reassurance. However they can also open the door to a lot of anxiety and stress, down a route you’d often rather not go down (despite my confidence before that I’d want to know everything 😅).

Wishing you the best of luck on your journey xx

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positivebex Thu 08-Apr-21 13:35:10

Thank you I really appreciate it. No matter opinions and preferences just nice to find people talking about realities of all of this. I see a lot of threads of people recommending people have NIPTs etc and that will give them the reassurance but as you say everyone’s circumstances are just so so different and so many factors involved and like everything pro’s and cons. I would just argue to anyone to try and get all the facts and do what is right for them.

SarahD19 Thu 08-Apr-21 13:57:24

I completely agree with you! I sometimes get a backlash on this page for highlighting some of these points however 🙈

Wishing you all the best with your test results and pregnancy. Happy to chat via PM is I can be any support too xx

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Poptart90 Mon 03-May-21 19:30:29

I really appreciate this thread, especially the link you shared in your first post.
Me and my partner are carriers for a rare genetic condition, we found out about it when my son was born and almost died due to not knowing he had the condition. I am pregnant again and we are going to be having CVS testing done to see if this baby has it so we can have a plan in place for after they are born. I have been really anxious about it, even though I know it's absolutely what we want to do, I'm so scared of the miscarriage risk. NIPT is not an option for us. The article you shared has been really reassuring so thank you again for sharing and starting this thread

SarahD19 Mon 03-May-21 21:19:21

@Poptart90 thank you for your message. It sounds like you have been on a real rollercoaster! I hope your next pregnancy/birth experience is smoother for you. Best of luck with your CVS! I’ll be thinking of you xx

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Hoowhoowho Mon 03-May-21 21:31:35

Of course declaring Edwards’ syndrome incompatible with life is the first thing that should be robustly challenged.

Severely life limiting? Probably. Though to declare a condition where even basic treatment like oxygen is routinely denied ‘incompatible with life’ is a bit strange. It might be more ‘compatible with life’ if basic care was actually provided.

I will never forget watching a newborn dehydrate to death because IV feeding was denied on the basis of a trisomy 18 diagnosis. Not ethical and not okay.

I agree with you re NIPT but I understand if you plan to continue the pregnancy that NIPT gives you time to prepare for a likely trisomy diagnosis and to advocate for the pregnancy and post birth care you want. If it’s wrong then great.

However terminating on the basis of a positive NIPT is risky.

SarahD19 Mon 03-May-21 21:48:55

@Hoowhoowho agreed. However given NIPT can be taken as early as 9-10 weeks, there’s higher risk of zygotic rescue - and anomaly scan cannot occur until around 20 weeks pregnant, I find the likelihood of a person being left in limbo for about 10 weeks quite problematic. Especially given almost 2/3 of positive Trisomy 18 detections through NIPT are “false positives” (across the general population anyway). NIPT clearly has it’s place within the context of risk assessment, but we also have a duty of care in terms of considering psychology impact, ensuring appropriate support and counselling etc.

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Hoowhoowho Tue 04-May-21 15:46:31

You might like a book called ‘the Tentative pregnancy’ which was actually written around the time of amniocentesis becoming commonplace but a lot of the concerns apply doubly to NIPT.

I had NIPT in my fourth pregnancy, was reassured by the negatives. Had it been positive for T18 or 13 we would have prepared for the massive fight we’d have on our hands for decent treatment and accepted it may be a false positive. We likely wouldn’t have opted for diagnostic testing.
If on the other hand we would have terminated then of course we would have had diagnostic testing.

Straightforward counselling regarding options is important and every woman gets to make their own choice. An anomaly scan may not confirm or deny T18 either. I know plenty of people with post birth diagnoses. Ours was nearly missed.

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