Second Trimester DS screening

[debbiex14]

Good Morning,

I suppose I'm just looking for some reassurance while awaiting results from my amino carried out yesterday ..

On Monday we received a phone call from Fetal medicine confirming we are high risk DS, my result was 1:140, I am 32, 19+3weeks pregnant, the result is purely based on bloods taken at 18 weeks pregnant.

We have been failed by our hospital with this pregnancy, they missed ample opportunity to process 1st trimester screening but will deal with that after the outcome of our results!

We had the amino carried out yesterday and will have our result by Friday, I'm an anxious mess and convinced myself our baby has DS, we have 2 kids aged 9 & 3 and just don't know how I will cope, my mental health isn't the best xxx

I have no assurance I'm afraid but I am currently awaiting Harmony test results after 12 week scan - my odds are 1:34. I'm so worried. I also have other young DC. Handhold 💐
However midwife did point out to me that 1:34 is still only a 3% chance so yours will be even lower than that - I am trying to focus on that x

Hi ladies, just to reassure you, other lady's on this thread have had 1/2 chance of Down syndrome and been totally fine! As for the nhs screening I feel it's very very inaccurate I'd take it with a pinch of salt. Harmony test however is very very accurate it's a blood test that extracts fetal dna 🧬 from mum that comes from baby and gives you a 1/10000 chance or 99% chance of a baby with a chromosome abnormalitie. So I highly recommend that as it's less invasive and accurate. I hope you get the results u want x

Thank you @hols86 🤞🤞x

Sorry to hear you're going through this. Did you have the screening on time but they just processed the results really late? That's not how it should be at all.

Luckily you've had the amnio now and you should get your results soon. In my second pregnancy we were given a risk rating of 1:95 (or thereabouts) but the results came back clear. 1:140 doesn't sound too bad to me, and hopefully you'll get the all clear too.

Luckily the results are quick if it's just the first three trisomies, so you should know very soon. I think our latest results only took about 24 hours (but this was years ago). Hang in there. It's horrible but you will know soon.

Thanks Ladies - just reassuring & distracting to speak to people in a similar position, I haven't slept since Sunday night (got the phone call on Monday lunchtime) midnight googling is probably doing me more harm than good!

@BabyPotato my booking in app was due the week after Christmas (Covid relaxation) my app was cancelled & I was sent 2 new apps for 2nd & 4th Feb, by then I was 14weeks!! Attempted first trimester screening with the bloods, sonographer was awful and didn't even attempt to measure fluid behind baby's neck and was extremely rude to both myself & partner on the one occasion she spoke to us!

Fast forward 16th Feb had an app for 2nd trimester bloods, due to complaint regarding first scan the hospital were too busy covering tracks & giving us a lovely detailed scan that my bloods were FORGOTTEN ABOUT!! Honestly couldn't make it up!

Bloods were taken on 2/3 which has resulted in us being in this mess.

I totally appreciate the outcome is the outcome & what will be will be but I would have been much more content in my decision making should I have found out earlier in my pregnancy

Hey as another poster has said, NIPT is very sensitive at detecting Downs Syndrome and if you get a negative NIPT, that is very reliable. However, feel the need to clarify the following:

• The NIPT targets cell free DNA, which OFTEN but not always, resembles the foetus. Cells can come from the placenta or even maternal cells, which may not be representative.

• If you have a positive NIPT result, this is around 80% accurate, so there is still a possibility the test is wrong.

• Positive NIPT for other conditions is incredibly unreliable with Positive Predictive Value (PPV) below 50% (sometimes much lower) for all other conditions. This means if other conditions are detected, unless there are other features such as ultrasound markers, the test is most likely wrong.

• Unfortunately the education around screening tests including NIPT is dangerously limited and so the test is misrepresented.

The NIPT is extremely sensitive (i. e. It is unlikely to miss Trisomy conditions), but it is so sensitive it throws up a lot of false alarms too (detects Trisomies that are not related to the foetus). People mistake the sensitivity of the test for PPV and give far more credence to the results of these tests than is clinically safe to do so.

@SarahD19 Sorry I'm not that science-y! Are you saying it's more likely to get a false positive for any of the conditions than a false negative?

I'm looking into clinics today to book mine in 2 weeks but if the results were negative for all conditions, I can trust it?

Yes there's a possibility of a false positive, but not for a false negative, it would be extremely rare. X

I've never heard for a false negative, they would not give u a result if they didn't get enough fetal dna to get an accurate result, u need atleast 4% fetal dna to get an accurate result X

@RuthieJ85 yes false positives are quite common with pretty much all conditions, especially if not Downs Syndrome. False negatives do happen but are rare with NIPT. If you have a negative result that should reassure. Good luck! X

The condition where the placental cells do not match the fetal cells is Confined Placental Mosacism and from what I have read it occurs in around only 2% of pregnancies- it is pretty rare. But positive NIPT result should still always be confirmed with a CVS or amnio.
Accuracy of NIPT for trisomies other than 13,18 and 21 is much poorer. eg Turners Syndrome. It's mainly private clinics that run these tests, the NHS does not encourage using it to test for these.
The rate of false negatives is* very* low. The rate of false positives is unfortunately also low, getting higher depending on your background risk
ie someone in their 20s already has a low background risk of an affected pregnancy so the PPV is lower for them. For someone older (like me) the existing risk is higher and the NIPT is more accurate, particularly for t21. It varies depending on the particular brand of test and person, but the chance of false positive in my case was about 0.1%. (PPV >99%). Even a PPV of 80% is still only a 1 in 5 chance that the results are wrong. Hopefully as the test is used more the stats will be clearer and results more reliable.
I've been there, read everything and looked for any sign of a chance that our result was wrong. I wouldn't want people to read the posts below and raise their hopes unfairly.
I hope so much that they are the 1 in 5. Everyone should ask their Drs all the questions they need to and do your own research about the test.
I definitely agree the NHS does still have work to do in how this test is explained and the subsequent counselling offered post results, it was really lacking in my case.

(Sorry correction -CPM occurs in around 2% of CVS samples taken not pregnancies- typically indicating an already higher risk pregnancy)

@sickofthisyear sorry had to add that the PPV for Edwards is only around 37% from NIPT and 49% for Patau’s. NIPT should only really be considered a Downs screening imho. And I also hear even clinicians overlook that a positive screening can be wrong in 20% of cases.

Also in terms of confirmation of conditions, neither CVS or amniocentesis are fall proof or straightforward. In some reasons there are obstetric issues which means these procedures are not viable. Additionally the statistic of 1-2% for mosaicism in CVS is misleading. In fact with a number of conditions such as Trisomies 13 or 18 the CVS will have only 75-80% PPV due to conditions such as mosaicism. The 1-2% mosaicism is for all CVS tests, not all positive detections via CVS. This is yet another example of how statistics are often misrepresented.

Fetal Medicine is a much more complex and complex picture than is often portrayed.

• fool-proof not fall proof

There can be a number of reasons for false positives in NIPT:

• Confined Placental Mosaicism.
• Zygotic Rescue.
• Vanishing Twin Syndrome.
• Maternal Mosaicism/Partial Trisomy.
• Underlying maternal conditions.
• Undiagnosed early miscarriage.

These are just the ones we have some information about, and there are arguably many unknowns and overlap with these factors.

Bottom line NIPT is taking blood from a pregnant woman and analysing Cell Free DNA. It is basically guess work and estimates whether the bloodworks comes from the placenta. So NIPT tries to analyse the placenta indirectly.

CVS is just a biopsy of the placenta. We only learned just over 30 years ago that this is not always the same as the foetus. This can be due to CPM as already explained (foetus and placenta don’t match). Given CVS might only have 75%-80% accuracy in some instances (such as with rarer trisomies), you can imagine that with all those other factors, it stands to reason how NIPT will be far less accurate.

Even amniocentesis only analyses amniocytes in the hope of accessing foetal cells. This will be the most accurate of tests, but even this test is flawed.

The stat of 37% applies to NIPT carried out in the general population of pregnant women. When NIPT is performed for women already given a high chance result the PPV increases (significantly). I found the document linked quite thorough- it seems to challenge the test fairly.

www.nuffieldbioethics.org/wp-content/uploads/NIPT-ethical-issues-full-report.pdf

@sickofthisyear I agree. This is where the trouble lies imho. I completely understand when there are risk factors that NIPT has it’s place with proper counselling etc. Or even in the general population where these statistics are explained fully.

The difficulty I have is it being normalised as “almost diagnostic” and people taking the test for the sake of it or just a gender reveal, then being under the impression false positives etc are rare for the 3 main Trisomies. It leaves me very concerned when people take the test and report they’ve been told it is 99% likely their baby has a condition...

Yes, I don't think it should be offered outside of continuing/'official' prenatal care eg high street scan clinics etc. It should only be offered in a set up which allows for thorough pre and post counselling and care. And shouldn't be used for conditions where the evidence is less robust such as the sex chromosome conditions.
I was never told by screening staff that it was 99% certain, they just said I had a high chance result and we continued to amnio (which I knew was also more accurate than CVS).
For those (like you @SarahD19 and I) who are able to critically appraise and understand the studies and literature I knew there was only a minuscule chance that my particular result was wrong and prepared myself accordingly.
Unfortunately this was where my NHS care was lacking- the time from my NIPT results to amnio was 2 weeks and no one called me to discuss options/well-being etc. I fed this back to fetal med (who were amazing) and told them if it's going to be offered you need a clear follow up care plan for high chance results. It was as though until amnio my result 'didn't count' in terms of care, even though I knew very well that it did.
Forgive me if I'm rambling- it's Mother's Day tomorrow and I should have been due in two weeks. 😔
( for anyone reading who will find tomorrow difficult).

@sickofthisyear so sorry you went through this... Absolutely heartbreaking and I agree that continuity of care is so important.

We actually had the opposite experience in a sense. We had screening, CVS and amniocentesis, confirming Edwards Syndrome. We were in the allegedly tiny percentage/exception with every test in what turned out to be low level mosaicism.

We were basically presented with a very grim picture, which I challenged based on having read ample research - and a healthy ultrasound throughout the pregnancy (with just a scare that was not substantiated by Fetal Cardiology). We are blessed with a healthy baby girl and I know we are exceptionally lucky.

No doubt it is a very delicate balance how these tests are managed - as both our circumstances show. Sending you lots of virtual huge for tomorrow x

*hugs not huge (sorry for the typos)

@sickofthisyear I can't even imagine. Thinking of you today.

@sickofthisyear I was really shocked by your story about lack of care from the NHS. Honestly it terrifies me, a friend of mine is a community midwife and works in the screening team. She too was shocked to hear the lack of preparation between your NIPT and amnio. She explained me that in her team they have specialist midwife who's job it is to prepare and council all women in this exact situation. Which is reassuring... but if you're in their caseload...
I guess I just assumed the was blanket care wherever you are! Hearing your story has worried me significantly. I now feel it's up to me to (should I need to) to seek out advice, in case it isn't offered!

Where did you have your NIPT test? Did your midwife know you were having it?

I'm still going to go ahead with my NIPT but I'm thankful I have a close friend in screening who can help. But I agree, this shouldn't just be a luxury of "friends of midwives." It's absolutely the responsibility of healthcare professionals to offer adequate followup and advice.

Hi OP, I hope you're doing okay xx

@RuthieJ85 I can assure you from my first hand experience and what so many others have shared with me, that lack of continuity of care, plus misinformation, is extremely rife. It is extremely common and imho, the norm as opposed to the exception.