PRAGUE, Czech Republic, June 19 (UPI) -- Japanese researchers say they have developed a method for freezing human eggs -- called the Cryotop method -- that could allow women to delay pregnancy.
Dr. Masashige Kuwayama, scientific director of the Kato Ladies Clinic in Tokyo, says he first used the method of freezing eggs -- oocytes -- for artificial insemination in sheep and cattle.
"The Cryotop method is a highly efficient freezing procedure that opens a new way to resolve the various aspects of the problem of human oocyte cryopreservation," he says. "Using this method, we achieved a more than 90 percent survival rate for the freeze-thawed oocytes -- and a high pregnancy rate of nearly 42 percent after the oocytes had been fertilized and implanted in the women."
Kuwayama told a news briefing that although sperm could be frozen, thawed and used for in vitro fertilization with high levels of success, the freeze-thawing process could damage eggs and, until now, it had been very difficult to perform successful IVF using frozen-thawed eggs.
The findings, presented Monday, at the 22nd annual meeting of the European Society of Human Reproduction and Embryology in Prague, Czech Republic.
