I posted on here last week about numbers of embryos to transfer and got a lot of helpful and kind answers, so I'm back, now post-ET which was yesterday. The decision on how many to transfer sort of got made for us, because in the end we had 5 embryos fertilize out of 9 eggs. As of day 3, all were grade 1, but none had made it to 8-cell stage. One was 5-cell (possibly 6 by transfer time, going by the picture they gave us), 3 were 4 cell, and 1 was 3-cell. We transferred the 5-cell and all 3 of the 4-cell, and we're waiting to see if the 3-cell will grow to freeze, which it probably won't.
I know our chances are low, especially given my age. I've been Googling success stories with low-cell-count embryos, and there are some, but if I could get some here that would at least keep my spirits up a little through the 2ww. I go back and forth between having hope for the 5/6-cell one in particular and feeling in despair since this was our one and only IVF cycle (we are OOP).