During the egg retrieval process not only is the egg retrieved but there is a cumulus corona of cells that comes with it. The cumulus corona is then separated from the egg, and the egg is looked at under a microscope. It can be hard to see the egg at first, because if the cumulus corona is degenerated then chances are pretty good the egg or oocyte is also degenerated.
Once the egg/oocyte is checked to be viable, usually a process called ICSI is performed on the egg. If everything goes well for the fertilization process, the combined sperm and egg become a one-celled zygote. That happens on day 1 after retrieval. by day 2, assuming the growth is occurring normally, the zygote cleavages into 4 cells.
Now because I am 9, when I hear the word cleavage(d) I think boobs. However in the IVF world it means that the egg has split and the cells are multiplying.
My most recent zygote has cleavaged and become 4 cells.
I won’t hear what happens between now and Tuesday unless it arrests or becomes a blastocyst. I’m crossing my fingers toes and eyes until Tuesday, and will probably start frantically working on some new projects to keep myself from obsessing over the little bundle of cells that Molly who I love, is er.. embryo sitting.