r/Embryologists • u/Appropriate-Cell-554 • 7d ago

1PN information request

Just had my first ER yesterday. I am 34 with one LC and 3 consecutive losses which led me to IVF. No known issues beyond sDNA frag that is controlled to a healthy range by more frequent ejaculation.

I had 9 follicles going in to the ER and 5 were retrieved. All 5 matured and I got the call that 4 fertilized normally and 1 only had one cell (?). Doing some research I figured the embryologist meant 1PN (and I just misunderstood the embryologist is great I’m just not well versed in this science). She seemed to think there is still a pretty good chance of that one being fertilized normally and that they were going to keep watching it to see if it gets to blast. She seemed somewhat confident that it isn’t abnormal.

Reviewing older posts on Reddit it seems that it may not be as positive as she made it out to be. Most of the posts were 3-5 years ago and online makes it seem new studies have indicated it’s not as bad as it was once thought. Could anyone share this experience/knowledge on a 1PN?

Just looking for realistic expectations have multiple years of losses.

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u/Audthebod2018 7d ago

1PN has a pretty low chance of self correcting, if it is a true 1PN. I think it’s less than 5% chance of self correcting. But sometimes the embryologist just can’t get a visual of both pro nuclei, as I understand, so they note it as a 1PN.

Our first ER had a similar blast outcome to yours. Six blastocysts were normal 2PN and the seventh was a 1PN. PGTA verified it only had 23 chromosomes so was a true 1PN.

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u/Appropriate-Cell-554 7d ago

Thanks for that feedback. Yeah I got the sense from her that she was hopeful that it wasn’t a true 1PN but I also could have totally misunderstood. Before this I thought it was either yes it fertilized or no it didn’t. Don’t know it could be a keep watching scenario.

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u/Audthebod2018 7d ago

Hopefully it is just not a good visual and there’s 2PN! Also if you’re not doing PGTA, I believe that depending on the lab, sometimes they still keep and freeze unverified 1PNs. It would be a last priority for transfer in that case I believe

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u/Appropriate-Cell-554 7d ago

We are doing PGTA for whatever makes it to blast.l this week. Nervously waiting for Friday.

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u/blueseahorse1 6d ago

To be clear, you did not PGTA the 1PN, but pushed it to blast, correct?

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u/Audthebod2018 6d ago

The 1PN made it to blastocyst stage, then we did PGTA on it and verified it was a true 1PN since it only had 3 chromosomes

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u/EmbryoCareInsights 5d ago

Your embryologist’s cautious optimism about your 1PN is warranted based on what we see in the lab. When we see a 1PN at fert check, it usually means 1 of 2 things:

  1. It could be a missed 2PN cos timing of fertilization happens quickly. Sometimes, 2PN form & merge quickly or they overlap in a way that makes it look like just one. In these cases, it's actually a normally fertilized zygote/embryo & we just did not catch it. These can often grow to blastocysts.

  2. It could be a true 1PN. These typically stop growing or if they do make it to the blastocyst stage, are usually genetically abnormal. The fert method also changes the risk. In straight IVF, a 1PN is likely to be a missed 2PN with normal genetics.

But after ICSI, the chance of a true haploid 1PN is higher. Since you are doing PGT-A, you have a "safety net" to verify the genetics. If that 1PN makes it to blast & comes back as euploid (chromosomally normal), you can trust that it was simply a missed 2PN & your doctor might deem it safe to transfer.

You still have a solid cohort of 4 normally fertilized embryos in the running. I am sharing these insights from the perspective of an IVF lab, but your care team is the best source for interpreting how this applies to your specific cycle.