What is Ovarian Tissue Cryopreservation?

Unfortunately, emergency IVF is not available to all women with cancer, particularly girls who have not gone through puberty or those who cannot postpone cancer treatment. Members of the Oncofertility Consortium at Northwestern University thought that these limits could be overcome if a section of ovarian tissue containing eggs could be removed and frozen, then thawed at a later date. A major goal of their research is to develop methods that will allow the eggs within the thawed ovarian tissue to be matured within the laboratory (called in vitro maturation or IVM), then fertilized to create embryos as in traditional IVF. Alternatively, the thawed tissue could be transplanted back into the woman at a later date so that the eggs can mature in the woman’s body rather than in the laboratory.

Successfully freezing and thawing ovarian tissue and maturing eggs within the laboratory would represent a breakthrough in fertility preservation for women diagnosed with cancer for many reasons. First, the surgical removal of ovarian tissue would not cause a delay in cancer treatment for more than 1 or 2 days. Also, the procedure would not require hormone treatment, which is not appropriate for girls who have not yet undergone puberty. In fact, because a woman is born with her lifetime supply of eggs, girls as young as 1 year of age could be eligible for this procedure.

Finally, since this procedure would not require immediate fertilization of an egg, it allows women who do not have a partner or access to donor sperm more control over both when and with whom to have biological children.

Though removal of ovarian tissue is an established procedure, the techniques for freezing and thawing the tissue and use of the thawed eggs in IVM and IVF are still experimental and have not been tested in humans. The members of the Oncofertility Consortium are working to improve these techniques with the hope that they will be available in the future.