Eggs are frozen as a single cell on the day of egg retrieval of a IVF cycle. Embryos are most often frozen on day five of embryo growth, at about 100 cells. On average, 1 in four embryos are able to grow to this stage. At 100 cells, the embryo has a good chance of implanting in the uterus, and a better chance of freezing/thawing.
Published on Jul 11, 2012
An embryo is formed by fertilizing an egg with your partner's sperm and can be easily frozen for future use. An egg that is frozen would still have to be thawed out (and survive the freeze/thaw) and then fertilized with your partner's sperm (or donor sperm) in order to create an embyro that could be used for pregnancy.
Published on Jul 11, 2012