IVF program who had up to six treatments over a period of up to two to three years. “What you can see here is that the number of oocytes retrieved in successive cycles does not fall off, suggesting that we’re not pulling oocytes away from the next cycle each time we do a stimulation, and there doesn't seem to be any attrition in the response.”

A study of women from a Spanish IVF program reached a similar conclusion. These women donated eggs from one to nine times with a median of four months between cycles, so some of the women experienced hormone treatments stretching out over as much as three years. “Although the numbers are very small at the high numbers of cycles,” Dr. Cataldo said, “if you look at just the first 4 or 5 cycles, there appears to be absolutely no fall-off at all in terms of the ability to recruit roughly 15 or 16 oocytes per cycle from these donors in repeated use.”

So as far as either basic ovarian physiology or clinical experience indicates, there is no reason to think that repeated ovarian stimulation poses a risk to a woman’s long-term fertility. Still, Dr. Cataldo said, not everything is known on the subject, and there are several potentially important questions that have not yet been answered.

It would be helpful, for example, to have a longitudinal study that followed women who had ovarian stimulation all the way to menopause to find out what their reproductive future holds. Do women who have donated their eggs experience higher rates of infertility? And, if so, are there characteristics among these women at the time of their donation that are predictive of the later infertility? Are certain forms of infertility more common among woman who have donated than among the general population? And the ultimate milestone: Do women who have donated their eggs undergo menopause at an earlier age?

SUMMARY: WHAT WE KNOW ABOUT THE RISKS OF OVARIAN STIMULATION FOR OOCYTE PRODUCTION

To increase the number of eggs that can be retrieved from a donor, the usual strategy is to put the donor through a regimen of hormone shots that (1) keep most or all of the donor’s antral follicles continuing down the path to maturation instead of just one; (2) prevent the follicles from ovulating before the desired time; and (3) when it is time, prepare the follicles for the harvesting of the oocytes. The hormones used in this



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