Egg & Embryo Freezing

Cryopreservation, also known as "freezing," involves storing embryos at a very low temperature so that they can be thawed and used later. Many fertility clinics now offer patients this option.

There are many reasons for using cryopreservation. It is often done when there are more embryos than are needed for a single in vitro fertilization (IVF) cycle. The extra embryos are saved and potentially used during later cycles.

IVF success rates are generally lower with frozen embryos than with freshly fertilized embryos, although pregnancy rates with frozen embryos have been improving in recent years. The survival rate after thawing often depends on the quality of the embryos at the time of freezing.

Egg and ovarian tissue freezing

Egg and ovarian tissue freezing are experimental techniques being investigated for fertility preservation in women. These techniques have the potential to be helpful for women with cancer, as chemotherapy and radiation treatment can often have a harmful effect on fertility. In egg freezing, a woman's mature eggs are developed and removed using standard IVF techniques. They are then frozen before being fertilized with sperm, in the hopes that they can be thawed, fertilized and transferred back into the woman's uterus later.

In ovarian tissue freezing, the ovary or ovaries are removed laparoscopically, divided into small strips, then frozen and stored. Later, they may be thawed for transplantation back into a woman's body, or for use with in vitro maturation, an investigational technique in which eggs are matured in the laboratory, rather than in a woman's body.

It's important to remember that both egg and ovarian tissue freezing are experimental techniques. The American Society for Reproductive Medicine (ASRM), has recommended that these techniques be studied further before they are widely used.

To learn more about cryopreservation and its potential uses, talk with your healthcare provider.