By having her eggs frozen before she begins cancer treatments, a woman can preserve the hope of one day having a baby.

Freezing eggs is one thing; thawing them safely so they can lead to pregnancy is the challenge. In the past, efforts to freeze a woman's eggs, or oocytes, have not worked well because the cells are large. When the egg is thawed, ice crystals cause damage that prevents the egg from being fertilized.

U-M researchers looked beyond traditional techniques to a method of freezing cells called vitrification. This cryopreservation technique allows the eggs to be cooled fast enough that the transformation from liquid to solid is instantaneous. No ice crystals form and the consistency resembles a viscous glassy state. Research so far has used mouse oocytes but U-M expects to make the technology available in the clinic soon.

"With traditional slow-freeze techniques, just over half the eggs survive the thawing process. Using vitrification, we are getting 98 percent survival. For a woman with cancer, these are the only eggs she's ever going to have, so it's important that as many as possible remain viable," says Gary D. Smith, Ph.D., associate professor of obstetrics and gynecology, urology, and molecular and integrative physiology at the U-M Medical School, and director of the Fertility Counseling and Gamete Cryopreservation Program at the U-M Comprehensive Cancer Center.

Smith will present results of his research on Sunday, May 29, at the World Congress on In Vitro Fertilization, Assisted Reproduction and Genetics in Istanbul, Turkey.

Cancer treatments such as chemotherapy and radiation therapy can cause damage to a woman's reproductive system and leave h
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29-May-2005