Egg freezing, also known as mature oocyte cryopreservation, is a method used to preserve a woman's reproductive potential.Eggs are harvested from your ovaries, frozen unfertilized and stored for later use. A frozen egg can be thawed, combined with sperm in a lab and implanted in your uterus (in vitro fertilization).However, only a small portion of eggs that are frozen, thawed and implanted result in the birth of a baby. Egg freezing can also be expensive.Your doctor can help you understand how egg freezing works, the potential risks and whether this method of fertility preservation is right for you.