Placental Mosaicism??

[SarahD19]

Anyone else had a diagnosis of placental mosaicism??

I’ve had issues since my 12 week scan in mid-October. I was notified I was high risk for Edwards and Patau (1/85). Diagnostic CVS concluded Edwards to 99% certainty.

I was initially encouraged to consider compassionate termination as advised baby’s chances of survival were minimal. Was just starting to accept the diagnosis and get my head round this, when we got told 3.5 weeks ago that I actually have placental mosaicism. I was told this could mean baby is healthy and placenta essentially has Edwards. Amniocentesis was recommended.

Amniocentesis was only just viable to progress last week due to obstetric issues. This sample was then contaminated with blood and I’ve been told we have a 3 week wait for results which will take us to Christmas. I’m going out of my mind thinking I’ll be told my baby will die on Christmas week.

We’ve been referred to fetal cardiology and genetic counselling this week. Part of the issue is no one has heard of this condition and it only adds to my isolation. I wondered if anyone else has experienced this?

[Nanmumandmidwife]

It is an unusual situation, but certainly not unknown. It is a factor which we always have to be mindful of when interpreting NIPT or CVS results as the way both of these tests work is looking at cells from the placenta. As you have now learned, just occasionally the lab will be suspicious that the extra chromosomes (in your case chromosome 18) are only in the placenta, not in the baby.
Has anything unusual been reported on the scans?
It is certainly good practice to have a fetal cardiac review and the genetics team will be able to explain this all more fully. If confirmed as placental confined trisomy you will be offered extra scans and close follow up as the pregnancy progresses because it may affect the placental function. Apart from that I hope you will be getting a wonderful Christmas present.
However, this is extremely difficult for you and I have had patients who have opted to end the pregnancy anyway because they couldn't cope with the uncertainty.
Do message me direct if you want to discuss anything privately.

[SarahD19]

@Nanmumandmidwife thank you! There was a suspected VSD and fetal cardiology have now ruled that out. Otherwise good growth (actually a bit larger than average) and no markers.

[Nanmumandmidwife]

I will keep fingers and toes crossed for you! If there are no signs on scan & baby is well grow, I would suggest cautious optimism is reasonable. If growth slows down in later pregnancy I would be inclined to think that early delivery would be justified because of the uncertainty about placental function as baby's demands increase. Let me know how things progress x

[SarahD19]

@Nanmumandmidwife Thank you! I will do. My first baby was large for gestational age (98th centile) so growth should be interesting. During my first midwife appointment my worry was initially about how big this baby could be...

[Ruthsoph]

I had this
I had the NIBT at 10 weeks all come back fine then at my 12 wk scan the NT was 4.8 so I was advised to have a CVS - this came back clear on the first part but the second part mosaic Down syndrome was detected. So I had an amino as was advised that the mosaic DS could just be in the placenta
I had the amino and sadly it was found in the baby also and at a high %
Mosaic DS is detected in some cells and not all hence why it wasn’t picked up in my NIBT test
Heartbreakingly we opted for a termination as after a heart scan on Violet (that’s what we called her) it was found that her also had a poorly heart and I couldn’t bare her being in any sort of pain - we had the amino as we wanted to check every possible option
It’s a horrible time waiting and my heart goes out to you being in this situation x

[SarahD19]

@Ruthsoph I am so sorry you’ve been through this and so sorry for your loss.

We’ve just had the very positive news that the initial amniocentesis results are through (despite Initially being advised if a 3 week wait). The first result is clear of Edwards (T18)!! That and a clear echo, alongside scan showing such good growth, I feel a lot happier than I did writing this post. Finally some good news after 7 weeks of limbo and stress.

Still the final amniocentesis cultures to come. It looks promising though.... @Nanmumandmidwife

[AiryFairyMum]

That's great news. Sending lots of love.

[HalloweenCandyLeBonBon]

Fingers crossed for you op

[Ruthsoph]

That’s great news for you xx

[SarahD19]

@AiryFairyMum @HalloweenCandyLeBonBon @Ruthsoph

Thank you! Tbh I don’t think I’ll relax this pregnancy, especially as the final test results are not through. However it is certainly looking a lot more hopeful 🤞

[SarahD19]

Hello everyone. To update the long term culture has come through indicating mosaicism. Obviously this throws more uncertainty in our direction but we’re trying to stay positive.

[OhCumInMyFaceful]

Good luck with this. The uncertaincy must be awful.

[SarahD19]

@OhCumInMyFaceful thank you! Trying to be hopeful as initial amniocentesis result was clear and growth/ultrasound/echo etc still all very good.

It’s been diagnosed as “low level” mosaicism. The literature I read around this is mixed. Some say it can be asymptomatic or only have very low level health implications. Others say this is not necessarily the case.