Lots of embryos only made it to blastocyst on day 6

Hi Carole

I am so pleased I found this site and in particular your part of it. You are a great source of knowledge to have on here.

I have just completed my first donor egg cycle involving a frozen single embryo transfer of a blastocyst that had been biopsied on day 5 or day 6 (I need to check with my clinic whether this particular embryo was day 5 or day 6). I was not successful on this transfer. My donor is young - 24 and a proven donor. My husband has no known sperm issues. My lining was great prior to transfer and I have had two children prior to falling foul of the family history of early menoapuse.

I am now looking back over the cycle and thinking about things that might have affected my success (other than just falling on the wrong side of the stats). We got 9 blastocysts that met the clinic's standards for biopsy and freezing. However, when I got my update on day 5 only 3 were ready for biopsy then. The rest were biopsied on day 6. I guess my first question is why were so many of my embryos slow growing? Was it the sperm or the egg? Was it the protocol? Because we did GSN we know that there were no chromosomal abnormalities with these embryos but I suppose I am more asking about the metabolic health of the embryo.

My second question relates to what to do next and is similar to Jacqueline's earlier post. We have normal 1 girl frozen (my husband made 6 normal boys!) and we have the option of doing a FET with that embryo or doing another fresh cycle with my lovely donor (who is willing to do it all again for us). If it turns out my other girl was biopsied and frozen on day 6 what are my chances of success with such an embryo compared to a day 5 embryo?

Thanks so much in advance.

Dear Waiting for Scarlett,
I don't know why all the embryos didn't make criteria for biopsy on day 5; perhaps they needed to be more expanded or have more trophectoderm layer cells for biopsy? A matter of a few hours difference in fertilization time can make full expansion seem to take a little longer in one embryo compared to the other- say early on day 6 instead of late on day 5 when there's really not much difference between the two. I would ask your doctor if he thinks you are a good candidate for elective single embryo transfer and then I would go ahead and transfer the known girl embryo you already have. I am a big fan of single embryo transfer because a singleton pregnancy typically has the least obstetrical complications. Whenever you transfer more than one, you have an increased risk of twins and the possibility of premature birth. Plus, if this FET works, you have just saved a ton of money for little girl's college fund. :) Best wishes for whatever you decide. Carole

Hi Carole - thanks so much for your prompt reply - it is very much appreciated. I am pleased you don't seem to think it is particularly worrying that so many were biopsied on day 6 not day 5. I am a huge fan of SETs myself - I wouldn't do anything else in fact so no difficulties on that score. I just know my husband only has the energy for 4 transfers in total so I just want to maximise my chances of success re those transfers. I guess this is why I am wondering whether new cycle with the possibility of more day 5 biopsied embryos is the way to go (even though there would be significant extra expense).