Oocyte cryopreservation - allows women to freeze their eggs

Researchers at the Yale Fertility Center are now offering a cutting edge reproductive procedure called oocyte cryopreservation that allows women to freeze their eggs and use them at a later time to conceive a child.

Pasquale Patrizio, M.D., professor in the Department of Obstetrics, Gynecology & Reproductive Sciences and Director of the Yale Fertility Center, is introducing this technique at Yale in collaboration with an oocyte cryopreservation expert from Bologna, Italy. They will also be researching ways to improve the success of the technology.

Oocyte cryopreservation is aimed at three particular groups of women: those diagnosed with cancer who have not yet begun chemo- or radiotherapy that is toxic for oocytes; those undergoing treatment with assisted reproductive technologies who, for personal reasons, do not consider embryo freezing; and those who do not have a partner and would like to preserve their future ability to have children.

Preparation for oocyte cryopreservation includes consultation, evaluation, and instruction on the use of fertility medications to increase the number of naturally produced eggs. The patient is monitored throughout this outpatient procedure.

Patrizio said the currently reported overall success rate is around two to three babies born per 100 eggs preserved. Compared to conventional in vitro fertilization with non-frozen eggs--eight to nine babies born per 100 eggs--these rates seem low, but are likely to increase as the technique, which is still considered experimental by the American Society for Reproductive Medicine, is refined. Success also depends on the age of the donor--eggs frozen from women before age 35 have a better chance of producing a successful pregnancy.

For patients with cancer, Patrizio, with the help of Emre Seli, M.D., assistant professor in the Department of Obstetrics, Gynecology & Reproductive Sciences, will work with oncologists to help preserve future fertility in younger cancer patients.

"As in the early days of in vitro fertilization, this procedure is still evolving," said Patrizio. "Embryo cryopreservation as an alternative to egg cryopreservation has a higher success rate, but it is not an option for many women."