[quote=no_such_reality]Navydoc, you didn’t say anything.

What is the probability an embryo splits? 32 out of 1000? That’s one, two concurrent splits?

[/quote]

The answer to your question is not completely known. The chance of a spontaneous embryo splitting in a natural pregnancy is 0.42%, but, as we all know, this is anything but a natural pregnancy. I also can’t meaningfully respond without knowing more about her specific IVF procedure. Twinning rates are higher if intracytoplasmic sperm injection was used to make the embryos, a real possibility, since in this case she used donor sperm. When a patient conceived via IVF we always get a report from the REI staing how many embryos were transferred, and I agree, 2 splitting events simultaneously would be unusual, just not impossible.

Much of the work in IVF is focused on making the best posssible embryo quality, and unfortunately, we often don’t know what will happen until after the fact.