Few other studies have looked at the effects of egg-harvesting procedures on the future reproductive health of women who donate eggs.

Some experts question whether hormonally stimulating the ovaries -- which makes them produce extra eggs -- and removing those eggs from a healthy, young woman could later increase her chance of infertility, but others contend there are no serious long-term risks.

"Egg donation has been offered to patients in Belgium since the 1980s. We were not surprised by the good reproductive outcomes in ex-egg donors," Dr. Dominic Stoop, medical director at the Center for Reproductive Medicine in Brussels, Belgium and lead author of the study, wrote in an email to Reuters Health.

The researchers gave a telephone questionnaire to 194 women who had donated eggs at the Belgian center between 1999 and 2010. The surveys were conducted an average of four to five years after those procedures.

At the time of donation, women averaged 30 years old.

Sixty past egg donors reported trying to get pregnant since the procedure. Of those, 57 women conceived without help. The other three women required fertility treatment, though two of them sought treatment because of their partner's infertility.

Sixteen percent of donors had changes in their menstrual cycle after donation. However, none of the women reporting these changes had fertility problems.

"Menstrual pattern could be disrupted temporarily by hormonal changes due to ovarian stimulation, much like how menstrual changes also appear after stopping an oral contraceptive," said Stoop, whose study is published in Fertility and Sterility.

"In the short term, egg donation appears to have no effect on fertility," said Dr. Orhan Bukulmez, an infertility specialist at University of Texas Southwestern Medical Center in Dallas who wasn't involved in the new research. But longer-term studies of egg donors are needed, he told Reuters Health.

Although some researchers argue that the extra hormones women are given before the procedure and possible trauma to the ovaries during it could lead to early menopause in egg donors, studies haven't found reasons to be concerned so far.

Egg donation is a well-established form of fertility treatment. In the United States, roughly 12 percent of all treatment cycles in 2009 used donor eggs, according to the Centers for Disease Control and Prevention.

Future research is needed to also consider possible fertility risks for women who have their eggs harvested and frozen for their own future personal use, according to Stoop.

Originally explored as a way for women undergoing cancer treatment to preserve their fertility, the American Society for Reproductive Medicine still considers that type of egg freezing experimental.

Bukulmez cautioned that the results of the current study cannot be generalized to include women seeking to freeze their own eggs.

Egg donors are a very select group of patients that are chosen for their healthy ovaries, according to Bukulmez. "They may not be representative of the fertile female population as a whole," he said.

SOURCE: bit.ly/HH3I9F Fertility and Sterility, online April 1, 2012.

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