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Genetic testing of frozen embryos - any advice?


I just wonder if anyone has had preimplantation genetic screening of frozen blasts to test for genetic normalcy (ie would need to be defrosted, biopsies and refrozen)? I’m seeing my Consultant on Friday to discuss but grateful for any experiences others have had, balance of risks and benefits and ultimate pregnancy outcomes when those deemed ‘normal’ have been transferred.

Following our MMC we have 5 frozen blasts remaining from our first IVF cycle. We could spend 6 months and more of pain / grief doing FETs with potentially no success. If possible I would rather know now if any of the remaining blasts are genetically normal. If not, maybe we go straight to another fresh IVF cycle and if yes we will hopefully increase the chances that any FET done would implant and also subsequently reduce the risk of miscarriage.

I know PGS is super common in the States but seems to be less so here in the UK. I wanted to do it on all embryos from our fresh IVF cycle but my Consultant recommends doing a fresh transfer and suggested the chances of having more than 1-2 blasts remaining would be small hence it wouldn’t be worth the cost involved in testing them. Even he was surprised that on Day 5 we had 7 good quality blasts remaining. It’s left me in a good, but difficult position given the heartache we’ve been through over the past few months.

Thank you for any help you can offer.

9 Replies

Hi Mogwai_2. I have known this o be done, and I admit that I wondered whether it was safe to use twice-frozen embryos. However it doesn't reduce implantation rate at all, so if you have an experienced embryologist who will advise you, then I think I would go for it. Your decision of course, but I do wish you well with the outcome. Diane

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Many thanks Diane. It’s helpful to get input from others when I know we’ll ultimately be told it’s our decision. Will let you know what we decide!

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Good luck with that. Diane


We’re faced with the pgs dilemma in our last two remaining frosties and just don’t know what to do for the best! Following your post with interest..... xx



Will keep you posted on what is recommended / what we decide. Will see our Consultant on Friday.

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Please do 👍🏻 xx



I met the Consultant this morning. He said it’s ultimately my decision as to whether to do PGS testing on our frozen embryos, but it’s not what he’d recommend.

He feels the data on implantation and pregnancy rates from the States raise questions about why PSG tested embryo implantation and pregnancy rates are not materially better than results from non-tested embryos in IVF. Essentially he feels we don’t yet know if there are risks associated with damaging blasts in the process.

His opinion in respect of my situation was that we shouldn’t risk our 5 blasts after 1 miscarriage, recognising we would be de-frosting, biopsying then re-freezing already frozen embryos. He feels we should proceed with a FET without testing.

He accepted that if we have a further miscarriage or an implantation failure that we might want to consider PGS on fresh embryos from a further IVF cycle and transfer back our remained frozen embryos after egg collection from that cycle. That would use up all but one of our frozen embryos if we transfer 2 each time.

My head is spinning and I’m still processing what he has told me to be honest. I do trust his judgement however.

Finally, and while perhaps not relevant to your current situation, he said that in the UK only genetically normal embryos that have been tested can be kept / frozen. This is not the case in the USA apparently. While one could argue why it would be worth keeping them if they’re not normal, there are now apparently studies showing that transfer of abnormal embryos in a small number of cases can result in a health pregnancy / baby (i.e. in some cases the chromosomal abnormality can self-correct). This is part of why he’s hesitant as he is concerned through genetic testing it is possible that one could throw away embryos that could create a healthy baby.

I’m not sure that this really helps you at all! He has given me his medical opinion, but that doesn’t take into account any of the emotion we all have to go through if / when it doesn’t work and therefore the desire to try to remove some of that risk if we possibly can.

If you do proceed with PGS, I’d just ensure you do your research on the best places in the UK to do it. Having a quality embryologist, using the latest niopsying techniques will be key. He said Care Fertilty is one of the UK leaders, but I have done no research on this myself.

Do let me know your thoughts once you’ve read / digested all this.

I feel bad as I suspect this isn’t overly helpful to you.


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Don’t feel bad. It’s as much as we expected after reading up on what the HFEA has to say about PGS. We left our last consultation thinking it was definitely the way to go but the more we’ve thought about it the more we’ve thought it might not be worth doing, for many reasons... Yes we are familiar with the theory that some abnormalities can correct themselves in the early stages.. I guess it depends the abnormality though.. Also it’s worth remembering that even if some of the embryos are genetically abnormal it doesn’t mean they all are. It’s just after losing two babies this year you have to try to make sense of why it’s happening. And of course there’s always the worry it could happen again! It’s interesting that your consultant doesn’t recommend PGS. I think we’ve probably decided to forget PGS on our frosties, but it feels a bit like being back to square one on how to progress. Thank you Xx


I just wanted to say it sounds like your consultant has given you good advice. I did a lot of research about PGS screening - we’ve decided to do it but on a fresh cycle and our circumstances are different. I have all the reservations which your consultant discussed. I think it sounds like you’re in good hands. All the very best of luck with your next frosty xxx


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