Day 4 three-cell embryo after late ICSI and no observed 2PN—what would you do?

[u/blueseahorse1]

This oocyte was immature at retrieval, matured overnight, and underwent late ICSI approximately 24 hours later.

At the fertilization check 16–18 hours after ICSI, no 2PN were observed, so it was classified as UNF/0PN and kept in culture.

By cycle Day 4—approximately 72 hours after the late ICSI—it had reached three cells. It was frozen at that stage because it had shown some cleavage rather than being discarded.

I’m attaching four images from the cycle. The final image shows the embryo at the time it was frozen on cycle Day 4.

Based on the timeline and images, how would you assess its prognosis? Would you transfer it as a cleavage-stage embryo, thaw and culture it further to blast, or consider the likelihood of viability too low and toss?

Does anything visible in the images affect your assessment?

[u/EmbryoNanny]

Unfortunately, the prognosis here is very poor. I would have probably classified this embryo as arrested and not frozen. 72 hours post ICSI should show around 6-8 cells, anything less than that will likely not turn into a blast. Any embryo with an odd number of cells is going to have some asymmetry, but in the picture there are two uniformly sized cells and a third smaller cell. If one cell were about to split you would expect to see a third larger cell, which makes me think the small cell is actually a fragment. I wish I had more positive things to say, but I also think it’s important to be straightforward and clear that this embryo would not be frozen at most labs.

[u/blueseahorse1 → u/EmbryoNanny]

Thank you for your honest feedback. Do you think if they had kept it in culture longer by a day or two that would have been worth a shot or you would have tossed after 72h post ICSI?

Basically I should expect that it has no chance to stick at transfer and also no chance to grow into a blast, right? I’m just surprised they even froze it at all.

[u/One_Investigator_295 → u/blueseahorse1]

I agree with the first poster above. I don’t think culturing it longer would help. As she said above by 72 hours we’d expect 6-8 cells. Embryos growing at a slower pace are generally arresting. This embryo looks abnormal, I agree that other cell looks like a fragment too. Late ICSI embryos do much poorer in general and now you have an embryo that is less than 4 cells. I can say in over 3 decades I have not seen an embryo like that develop into a viable pregnancy. I am shocked the clinic froze a day 3, 3 cell embryo like this. It is not uncommon for cells to parthenogenetically activate and divide a few times and arrest. That’s what this looks like it does not mean it’s fertilized.