Embryo freezing

Any embryos that are of good enough quality and 'leftover' from your IVF/ICS treatment can be frozen for later use. A frozen embryo that has been thawed is slightly less likely to implant into the lining of the uterus than fresh embryos, so we are very selective about the embryos we choose to freeze. We will freeze good quality embryos on day three or blastocysts on day five or six of development. Even if you become pregnant in your initial attempt you may wish to use your frozen embryos, if possible, to expand your family at a later date.

Embryos are frozen at an extremely low temperature with the use of the vitrifcation method. Vitrification is a technique whereby embryos are cooled at very fast rates in higher than former concentrations of permeating cryoprotectants/freeze-protecting solutions in order for the cell fluid/cytoplasm of the embryo to appear to be in a glass-like state i.e. it 'vitrifies'.