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Placental mosaic - what does it mean?

5 replies

lyra41 · 17/06/2005 06:32

I've recently had a CVS done and one of the dangers I had to sign to accept was "Placental Mosaic." The doctor either forgot to explain it to me, or I didn't take it in, and now I'm worrying what it could be. Can anyone in the know explain it in simple terms please?

OP posts:

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RedZuleika · 17/06/2005 09:34

I just had a google on this and everything online seems to be a bit impenetrable. Can you clarify: are you saying that the results flagged up 'placental mosaic' or that this was a problem that they would be looking for, or that this was a risk of the procedure, along with the small risk of miscarriage, which you had to sign to accept (in an 'informed consent' kind of a way)...?

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aloha · 17/06/2005 09:48

As I understand it, placental mosaicism is a finding of some abnormal chromosomes in some (but not all) cells of the placenta (which cvs samples). The tricky thing is that the abnormal chromosomes may just be in the placenta and not affect the baby, or they may affect the baby to varying degrees because the placenta is affected. if this result is found it is difficult to interpret the CVS and you will possibly need an amnio to clarify matters. However it is extremely rare and very unlikely to affect you in any way.

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milward · 17/06/2005 10:24

I had this with dd3. I had a cvs, as my dds nuchal neck was 5mm at 11 weeks. The cvs results showed abnormalities that were extreme. The docs said it could be confined placental mosaicism (cpm). This happens when the egg has made 8 cell divisions. 6 of these divisions go to make up the placenta and the rest go to make up the baby. What isn't know at the moment is if it is chance that sends the abnormal cells to the placenta or some selection mechanism. The uni hospital said that out of the thousends of mums it sees each year it might get one with cpm at the most. So it is very rare. The problem with the cvs is that the cells are from the placenta and not from the baby - only an amnio can obtain the baby's cells as they are in the amnio fluid. If there is an abnormal result that can't be explained by a medical syndrome then mosaicism is suspected. I had to have an amnio at 14 weeks to see what if our baby was effected. Luckily all was ok. The risks of cpm are poor placantal function & growrh so this was be monitored. I had ultrasounds & blood flow checked. It was a very stressful and difficult time. I'm pregnant now & have refused all invasive tests despite having a high risk of abnormalities.
Hope all goes well for you xxx

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milward · 17/06/2005 10:26

www.medgen.ubc.ca/wrobinson/mosaic/cpm.htm

see for more info

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lyra41 · 18/06/2005 09:27

Thanks so much one and all.

I haven't had the results from the CVS yet, I'm just worrying about what they could be.

Placental mosaicism is one of the many things they have to inform you about when you sign the consent form, and I hadn't taken in what it meant.

Milward

Thanks especially for your experience, mumsnet is fab for finding out specialist things like this from another mother's perspective isn't it.
Will be praying for your pregancy and baby - hope it goes well xxx