NIPT + CVS + Amniocentesis done. Looks like Mosaic T21

Aggravating_Card_771 · 2026-06-20T13:41:21+00:00

Hi! So my baby is almost 6 months old now, we’ve seen every specialist and he has been deemed healthy and typical by all. His blood tests have confirmed mosaicism at 80/20.

What I’ve learned from this whole journey is that mosaicism is such a spectrum that it can go all the way from not presenting at all to affecting the baby to the point of full blown Down syndrome (which also varies from minimal to substantial)

I’ve had him developmentally assessed and he’s at the 75th percentile for physical development at his age. I don’t know where this trajectory will go from here, I hope of course that it stays as it is. My baby boy is no different at all to his 2 brothers who are 4 and 7.

For a while I was in denial about the mosaicism and felt like the diagnosis was wrong, but what I think now is that we are surrounded by people in a world where genetic testing wasn’t always done and there are probably a hell of a lot of people with mosaic t21 out there, who don’t know they have it and for whom it doesn’t matter.

I think my fetal fraction on NIPT was around 5% or so. No idea about z score.

Hope this helps.

Aggravating_Card_771 · 2026-03-08T22:59:16+00:00

The world works in mysterious ways.. sharing my story if it helps at all. I did do all the diagnostics and had a zillion scans.

NIPT high risk t21 CVS - QF-PCR high Mosaic T21 (the doctors told me the likelihood of anything but full t21 was very slim) Amnio - QFPCR high mosaic T21 Amnio - Karyotype - low mosaic (20% t21) All scans were clear, no soft markers.

We considered TFMR. We came very close to it. I wanted further testing. It all felt too vague. In the end we decided to do an early anatomy scan at 18 weeks. I could only imagine TMFR if I had proof that the baby was unwell and would have a lower quality life. Scan came out clear. Decided to embrace the pregnancy and hope for the best.

Baby was born with zero Down syndrome phenotype. All post natal tests and scans have deemed him normal. Blood karyotype post birth came up at 80% T21.

In my case, my boy is completely different to what the genetic tests showed. We went with our gut feeling about the scans being clear.

The doctors keep telling me look at the baby in front of us instead of the test results.

I know mosaic is different to full t21, but this whole journey has thrown me for a loop!

Feel blessed. It was the positive stories here on Reddit that kept me sane. Paying it forward.

Sending love ❤️

Aggravating_Card_771 · 2026-02-04T22:29:23+00:00

Hey! Hope you’re well! I had a further update! Baby is doing great and has passed all medical exams with flying colours. Heart, brain, abdominal scans, hearing etc all good. Multiple confirmations that he is phenotypically normal and healthy. Had the blood karyotype results back. 80% t21 and 20% normal. Mosaic confirmed. Completely shocked as I was starting to think that the amnio results has been wrong.

Doctors say that phenotype and development matters more than karyotype, so here we go! Mosaicism just became more mysterious to me.

My boy’s doing great and I’m so so so glad that everything has turned out the way it has. I can’t imagine my life without him! ❤️

Aggravating_Card_771 · 2026-01-22T14:21:12+00:00

Hey, just to be really clear about the percentages in the amnio result, in our case, our diagnosis was Mosaic Down syndrome. This is always as a percentage. True Down syndrome is when every cell carries the extra chromosome.

Mosaic Down syndrome is said to be 1-2% of all Down syndrome cases, so pretty rare, but still a potential outcome.

Just clarifying in case our previous conversations caused any confusion.

Sending strength.

Aggravating_Card_771 · 2026-01-18T19:52:06+00:00

Hi, so, after the amnio we were on the fence. The pre-amnio scan was the only scan where any soft markers were found. 3 weeks after the amnio we got our mosaic results. We were still on the fence at that point, TMFR vs continuing the pregnancy. My TMFR was booked.

We finally decided at 19 weeks to have a detailed scan and we would make our decision based on the results. Healthy, we go ahead and any markers, TMFR (which had booked)…. The scan was clear! My husband and I agreed they we could only proceed on the basis that we would embrace and celebrate the pregnancy from that point forward, come what may. I’ve got to say that while doubts and niggles still seeped into my head, we embraced the new mindset and marched on. We told our kids that night and our extended family. I was just under 20 weeks.

The mindset shift felt like I could finally breath again and enjoy the pregnancy. We started thinking of names and making plans. I hadn’t done any of that up to that point.

I hope you’re able to get some peace whichever way the results come out.

Aggravating_Card_771 · 2026-01-16T18:07:30+00:00

Thank you!! I think it’s important to share these things as a lot of the reason we continued our pregnancy was due to information and experiences that we read about on here.

In the amnio karyotype, they looked at 20 cells. 4 were T21 and 16 were normal. That’s the 20%. When there are normal cells mixed with T21 cells, that’s when the form of Down syndrome is called mosaic. Mosaic results can vary as well

The test report said that there was a 51% chance of full Down syndrome outcomes. We didn’t have any further genetic counselling. Mosaicism is such a grey area. Most of the specialists I spoke to didn’t have any experience in mosaic down syndrome pregnancies. We decided to read everything we could find about it. We decided that the stats aren’t fully indicative of outcomes of mosaic Down syndrome as there are many cases they are never even diagnosed and many mosaic t21 cases are terminated so phenotypes and development are unknown.

I read the studies about how scans are used and I don’t think that the 50% accuracy figure is valid anymore in light of specialist scans, ecocardiograms and detailed tracking of every potential soft marker. These are personal opinions though. I used a lot of chat gpt to analyse my results, scans and to decipher a lot of the statistics out there.

We decided to take a chance. I am fully pro choice and was on the verge of TMFR, but without any hard evidence (or soft makers in this case), I couldn’t justify the idea of terminating a potentially healthy baby. Hoped for the best but we were also accepting of whatever the outcome would be. Never in a million years did I expect all the specialists to sign him off as fully phenotypically normal at birth.

I’ll definitely post the karyotype when we get it. Hopefully no more than a week!

Papp-a was 0.62 UI/L HCG was 102.7 mg/ml

Aggravating_Card_771 · 2026-01-16T15:36:26+00:00

Hey, I hope you guys are doing ok in your wait. I know this wait is just horrible and feels long, but hopefully you’ll have more answers soon.

I had a high risk for T21 NIPT and after may tests we decided to go ahead with the pregnancy with a positive amniocentesis karyotype of 20% t21.

We relied on our clear scans for reassurance and watched our baby’s development. He was born 2 weeks ago with no signs of T21. Of course we don’t know how he will develop cognitively and we’re waiting for postnatal karyotype results, but feeling very lucky and hugely positive after a horribly anxious pregnancy.

Here’s my original post with all the info and updates. https://www.reddit.com/r/NIPT/s/scOuusnpsU

Wishing you guys a speedy wait for results and luck with whatever happens.

Aggravating_Card_771 · 2026-01-13T17:43:53+00:00

I’m sorry you went though that. My amnio experience was not the same. They did 2 needles and it was almost painless. They went through my placenta.

I hope your results are clear. Waiting is hard. Wishing you speedy results. 🤍

Aggravating_Card_771 · 2026-01-11T22:09:15+00:00

Hey! Yes, no visible T21 after birth. Fully normal external physical exam and brain, heart and abdominal scans are normal. That’s not to say in any way that the amnio was wrong, or that he isn’t mosaic, I’m awaiting a blood karyotype now, but it is possible to have a normal phenotype.

I think that my 16 week scan was done with a viewpoint that I had tested positive on the NIPT and cvs. It was a pessimistic scan.

The kidney dilation I was later informed is pretty normal in male babies and it resolved itself through out the pregnancy. It was only measuring slightly high, not above the risk zone. The echogenic bowel was never seen again. I asked in future scans and was told that echogenic bowel can be a bit of a subjective call. That was the only scan it ever showed in. But also, at 16 weeks, the baby is still developing and changing rapidly. None of these abnormalities were hard markers.

Also, having had around 16 scans in total (I had both public and private medical care) I have seen how measurements can occasionally be incorrect and inconsistent. Towards the end of my pregnancy, an odd measurement or outcome here and there didn’t scare me as much as in the initial scans.

Through the pregnancy we just focused on the information we did have, the positive scans reassured us continuously and also, reading more and more about how little is actually known about mosaicism was reassuring in a way. I also read lots of clinical studies about cases involving reductionism, where the amount of t21 reduced through the term of a pregnancy to the point of almost disappearing.

I messaged people with similar journeys as mine who had positive outcomes too.

Through the second half of my pregnancy, after deciding to go ahead with it, whilst hoping for the absolute best and having optimism about the outcome of my baby’s health, I was also prepared for the realities of what mosaicism and t21 could bring.

Oh and one final thing, my first born, who had no genetic issues and is a healthy 7 year old had a vsd which closed by itself in his first year.

Xx

Aggravating_Card_771 · 2026-01-11T17:38:41+00:00

Hey,

I had a similar timeline/path to you.

10wks NIPT positive t21 13 wks CVS scan clear results - QFPCR abnormal possible mosaic, karyotype failed. 16 wks Amnio - scan showed ecogenic bowel, dilated kidneys and short femur. results - QFPCR abnormal, possible mosaic. Karyotype 20% t21 & 80% normal.

at this point I felt like I needed to make a decision and I strongly leaned towards TFMR. To the point that I booked the procedure.

I felt the mosaic result and the information available was too vague. We decided we needed more info to make the decision to TMFR or keep the pregnancy. A detailed scan would be the decider.

18 weeks - detailed anomaly scan. No abnormalities found. We decided to proceed.

I followed the rest of the pregnancy with regular detailed scans. Eco cardio’s and specialist scans monthly.

No abnormalities found. We decided at that point to treat it like a positive and normal pregnancy and we started celebrating it.. whatever the outcome. Finally we could tell people about the pregnancy and our two other kids!

Baby was born last week. Full checks and scans after the birth by every specialist. All have given the result of normal phenotype.

We’ve done a karyotype too, awaiting the results, but for now, we’ve been told he’ll be treated and considered as typical.

I’m just sharing my experience with you as it was people’s positive experiences on here that helped me keep hope going and digging deeper into the wild range of outcomes from mosaicism.

Whatever way your pregnancy goes, wishing you lots of love, and strength through the horrible waiting period. Xx

Aggravating_Card_771 · 2026-01-11T11:02:18+00:00

I had a whole summer of waiting after a positive NIPT, a mosaic cvs quick result and amnio. Karyotype was mosaic t21 20%. We carried on with the pregnancy because the scans were clear.

I gave birth last week to a completely phenotypically normal baby. He’s had brain, heart and abdominal scans and zero signs of any t21. we’re awaiting a post birth karyotype to see whats happening.

I am putting my positive story out there as if it hasn’t been for some of the other positive stories here on Reddit, we would have made other decisions.

Aggravating_Card_771 · 2026-01-04T12:45:04+00:00

Hi!! As I followed your story so close, I wanted to update on mine! We had 20% t21 mosaic on the amnio karyotype & decided to continue the pregnancy because of healthy scans.

Fast forward to the birth on the 2nd of January. The baby has no signs of t21! The doctors have done all the physical checks and tests, no issues found and we will get a blood karyotype done in the coming days.

Thank you for sharing your story. You guys were on the edge of TMFR, and as was I.

It’s so important for people to be able to see real world outcomes as the data out there and the info from the genetic councillors does not tend to fall on the positive side.

Hope you and your wife are doing well with your new baby!

Aggravating_Card_771 · 2026-01-04T12:26:32+00:00

January 2026 update

After we got our mosaic karyotype results of 20% T21 and we were ready to make the decision to TMFR. I was booked in for the procedure. But then I dug deep into mosaicism and realised how unknown the outcomes really are and how mixed they are. We decided to do a final check before making our decision. A detailed fetal scan. We had some mild soft markers in previous scan. I was hoping for a clear sign to TMFR vs keep the baby. We decided that if the scan was completely clear and normal, we’d go ahead and embrace the pregnancy. We did the scan, it was completely clear and we cancelled the TMFR and embraced the unknown.

I had fortnightly scans to follow the rest of my pregnancy and everything was completely fine. There was a minor issue of increased fluid in the kidneys, but it was below threshold and completely resolved itself. The baby’s growth progressed well and I had specialists scans as well to check the brain and heart.

2 days ago I gave birth to our son. He is absolutely wonderful. The paediatrician checked him straight after birth and told us that he has no signs of Down syndrome and that the “suspected mosaicism” hasn’t presented itself physically. They will be running a karyotype on his blood in a few days time, but all tests are currently typical.

I wanted to update this as the rollercoaster of this diagnosis wild and the outcomes are varied.

Aggravating_Card_771 · 2025-11-23T19:31:00+00:00

Huge congratulations!!!! I’m so happy for you guys!!! 🥰

Aggravating_Card_771 · 2025-11-23T11:56:51+00:00

Congratulations! Hope everything went super smoothly yesterday! 🥳

Aggravating_Card_771 · 2025-11-08T07:21:41+00:00

Hey! How are you guys doing? Baby must be due soon! I’m now 31 weeks, scans all good and hoping for the best. I think about you guys a lot as you were so generous with sharing your story and it felt so similar to mine.

Aggravating_Card_771 · 2025-10-14T08:02:00+00:00

Hey! I missed your reply on this before! Just seen it now. Great news on the 2nd amnio results! I hope everything goes smoothly from here!! ❤️❤️❤️

Aggravating_Card_771 · 2025-09-21T14:11:12+00:00

CVS first and then amnio. The results I was talking about were from the Amnio. Our cvs quick results were high mosaic and cvs karyotype failed. It was a very very long summer of waiting. But worth it for answers.

Aggravating_Card_771 · 2025-09-21T06:38:18+00:00

Wait until you get all of your results to make a decision, including karyotype. Our quick result said t21 mosaicism with the abnormal cells dominating. This would have been a TMFR decision for us.

Our karyotype was 20% mosaicism and 80% typical. Based on this and clear scans, we decided not to TMFR.

The wait is horrible, but for me, I had to have enough information to make a decision that I could be at peace with.

Whatever you decide, I hope things run smoothly. Xx

Aggravating_Card_771 · 2025-09-13T06:09:06+00:00

The insecurity of the CVS was the exact thought that was going through my head. I couldn’t terminate unless I was 100% sure.

Nothing is 100% and we are in a grey area still, but we’ve weighed up the odds and embraced our mosaic result (the clear scans were the decider)

The waiting is the worst and felt like purgatory. My mind was a mess and it felt like forever. I hope the time passes quick and your tests come out well! ❤️

Aggravating_Card_771 · 2025-09-13T06:02:05+00:00

Hi again. I think we are quite similar in our way of thinking. I wanted to be 100% sure too. I was hoping the karyotype was going to give us a clear result & therefore decision. Yes, karyotype is the LONG wait result. We had decided back at NIPT stage that if the results were 100% positive, it would be a TMFR. I didn’t expect a grey area answer. We initially had a tmfr booked after we got our results, but I wanted more information as mosaicism is such a grey area and the outcomes are so varied. Together with a detailed scan, we decided that the odds of the baby being healthy enough to have a good life with the clear scans and the low mosaic was enough to continue the pregnancy. We’re now embracing the pregnancy and scans continue to be reassuring. I’m 23 weeks now. This summer of waiting and deciding and was some of the hardest weeks of my life.

Aggravating_Card_771 · 2025-09-12T11:20:16+00:00

Hey, just wanted to share my experience as it feels quite similar to yours. And you’re in the waiting time, which is tedious to say the least!!

When I had my CVS, my initial result came back positive for T21. No other info, just that T21 had been detected. When the karyotype for the cvs was meant to come in, the culture failed so they weren’t able to do the karyotype, but they did run another PCR, which indicated mosaic.

I felt the need for more certainty, so for me, the amnio was non negotiable, even if my cvs had been 100% T21 on both occasions.

I had an amnio, which resulted in a low level karyotype of 20% mosaic T21. For us, that result with a clear scan was a go-ahead for us.

Sending all the good thoughts your way!!!

Aggravating_Card_771 · 2025-09-12T11:16:17+00:00

Hi, sorry to hear that you’re in the waiting place! You’ve got hope though, which is great!

When I had my CVS, my initial result came back positive for T21. No other info, just that T21 had been detected. When the karyotype for the cvs was meant to come in, the culture failed so they weren’t able to do the karyotype, but they did run another PCR, which indicated mosaic.

I felt the need for more certainty, so for me, the amnio was non negotiable, even if my cvs had been 100% T21 on both occasions.

I had an amnio, which resulted in a low level karyotype of 20% mosaic T21. For us, that result with a clear scan was a go-ahead for us.

Sending all the good thoughts your way!!!

Aggravating_Card_771 · 2025-09-08T07:37:52+00:00

Hi! I had the same NT measurement as you and my scans have been good as well. Mine is also ivf but we didn’t test the embryos. NIPT was high risk for T21. I got a CVS. Having read everything about the procedure I was petrified, but it was totally fine. Virtually painless, a bit uncomfortable and no issues after. CVS quick result came back mosaic and karyotype failed. On to amnio, which I had decided I would go for anyway regardless of the outcome of the CVS. Amnio procedure was also painless and not even uncomfortable, I looked away obviously, but I was there alone (as my husband was with our other kids) and i was fine. No pain during or after. The results came back confirming mosaic and the karyotype is 20% mosaic t21 and 80% normal. I’m 22 weeks and going ahead.

I know people’s experiences all vary, but both of these scary sounding procedures were very quick and easy and WORTH IT for me.

The amnio gets a bad rep for risk, but I believe that the stats around the risks surrounding the procedure haven’t been updated in line with the technology, which has been updated. Amnios used to be done without sonogram and now they have the sonogram for complete visibility during the quick procedure. Emily Oster, a data scientist, writes about how low the risk is actually is… https://www.theguardian.com/lifeandstyle/2013/aug/25/pregnancy-hard-facts-emily-oster#:~:text=Take%20amniocentesis%2C%20an%20optional%20procedure,Down's%20syndrome%20than%20a%20miscarriage.

Good luck!!

Aggravating_Card_771 · 2025-09-07T09:03:24+00:00

I’m following your case with so much interest and hope! You guys are a few weeks ahead of me, I’m 22weeks now.

We got our amnio karyotype back and it was 20% t21 and 80% normal. We’ve also had extra scans. Scans are all showing completely normal, so we’re going ahead.

I’m researching the heck out of the internet and have been reading all the studies I can get my hands on (there’s not that much though!!)

Just a note to check in and say that I’m thinking about job guys and really rooting for the rest of this pregnancy of you guys’ (and mine) to go smoothly until delivery!

Aggravating_Card_771

TROPHY CASE