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Sep 7, 2008 10:33 pm US/Central
Freezing A Woman's Biological Clock
MINNEAPOLIS (CBS) ―
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Mayo Clinic has managed to stop the biological clock, in a sense, by freezing a woman's eggs for fertilization later.
CBS
One in six couples needs a little medical help to have a baby. Medicine can overcome many fertility issues, but it has not been able to buy a woman time -- until now.
Mayo Clinic has managed to stop the biological clock, in a sense, by freezing a woman's eggs for fertilization later.
Jonathon and Ceresa Caudill's twin daughters McKinney and Elizabeth are the first babies in Minnesota to get their start with the procedure.
"Going through the grief of infertility, and the struggles that that brings with it," said Jonathon. "When we finally got to this point and these little girls came to term it just meant all the more to us."
After two cycles of fertilizing Ceresa's eggs with Jonathon's sperm at Mayo Clinic fertility lab, there was no success. Still, the Caudills did not want to boost their odds by having many eggs fertilized for future attempts, because they could not imagine leaving unused embryos in limbo, frozen in storage.
"We felt most comfortable only having enough [embryos] that we could then transfer and then potentially bring to term," said Jonathon.
What the Caudills did allow Mayo to do is to freeze the extra eggs, or oocytes, they had harvested from Ceresa. That in itself is a very tough challenge compared to freezing an embryo.
The Mayo Clinic Obstetrics Lab's Dean Morbeck, Ph.D., says the many small cells of an embryo survive freezing better than a large, single-celled, water-filled egg. In the subzero cold of liquid nitrogen, ice crystals could be devastating to the egg.
"Because ... there would be chromosomes in this egg, and if ice crystals formed within those chromosomes it would break them apart and you would then have damage to it that would not allow it to fertilize normally or develop normally," said Morbeck.
Mayo's process of removing the water and slowly freezing the eggs allows half of them to survive the thaw to be fertilized. About 15 percent result in a healthy birth.
Initially, it was success in another area of medicine that had Mayo doctors so committed to making this procedure work. They were helping greater numbers of young people beat cancer. Unfortunately, many women of child-bearing age would find they had a lifetime ahead, but they had lost their dream of having a family.
"The radiation and chemotherapy specifically can be very damaging to either the ovary or the testical in these therapeutic measures," said Ob-GYN Charles C. Coddington, M.D.
Storing frozen men's sperm has been no problem for decades. But offering the same flexibility to women brings new hope to those who delay a family for a career or simply don't find the partner they want to have children with while the biological clock is still ticking.
Coddington estimates there are only 200 to 300 children in the world born to this technology so far. Mayo has teamed up with a national organization in Chicago called Fertile Hope which has a goal of helping cancer survivors preserve their ability to have children.
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