at risk for hyperstimulation. Other risk factors include irregular menstrual periods and low body weight.

It is also makes sense to try different modifications of the hCG part of the treatment, she noted, since hCG acts as the trigger for the hyperstimulation. One approach, for example, is to decrease the hCG dose. A second would be to use recombinant LH in place of the hCG. LH has a similar effect to the hCG but has a shorter half-life, so it does not remain in the system as long and therefore might not be so likely to cause hyperstimulation. There is preliminary evidence to suggest that both of these approaches decrease the occurrence of ovarian hyperstimulation.

In summary, Dr. Cedars said, she thinks oocyte donation for research can occur safely. It is not possible to completely eliminate ovarian hyperstimulation, but it is possible to limit its incidence and severity. A strategy for doing that might include excluding women from donating their eggs who have irregular menstrual cycles, who have ovaries with a polycystic appearance, and perhaps even those with high levels of androgens, as well as modifying the hormone treatment regimen to minimize the factors that are known to make hyperstimulation more likely, such as a higher than normal egg follicle count.

POTENTIAL RISK OF CANCER

One of the most serious concerns about ovarian stimulation is that it may increase the chances that a woman will suffer certain types of cancer later in her life (see Figure 2-3). In particular, said Roberta Ness, chair of the Department of Epidemiology at the University of Pittsburgh, there are three types of cancer that would seem to have a plausible biological link to the hormone regimens used in ovarian stimulation: breast, ovarian, and endometrial cancers.

Breast cancer, she noted, is the most common form of cancer among women and the second most common cause of death for women. Ovarian and endometrial cancers are not as common but are still dreaded among women because of their fatality rates.

There are several reasons to be concerned that the hormones used in assisted reproduction might make these three cancers more likely, Dr. Ness said. First, all three of them seem to be affected by hormones. The cells of these three types of cancer all have estrogen receptors, for example, and women who have had children, women who have breast fed, and



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