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Assessing the Medical Risks of Human Oocyte Donation for Stem Cell Research: Workshop Report
1992 through 2005, there was not a single case of severe OHSS, Dr. Rosenwaks said.
There are other ways to modify the hCG ovulation trigger without completely cutting it out, Dr. Cedars said. “One is to decrease the dose of hCG, because part of the reason that you get that hyperstimulation three to seven days after the injection of hCG is because of the long half-life of hCG. So if you decrease the initial dose, you decrease the time in which hCG levels are circulating and high enough to cause the continued stimulation to the ovary, and there’s some evidence to suggest you can decrease the occurrence of hyperstimulation.”
It is also possible, she noted, to use recombinant LH, which has the same effect as hCG of inducing ovulation, but it has a shorter half-life and thus does not stay in the body as long. There is some preliminary evidence suggesting that this technique decreases the occurrence and the duration of ovarian hyperstimulation.
As doctors and medical researchers learn more about the way that these hormones work in the body, more options will undoubtedly open up as well, but today we already have the capability of avoiding severe OHSS almost completely, Dr. Rosenwaks concluded. “With careful donor selection, individualization of stimulation protocols, careful monitoring, and utilizing appropriate preventive measures, severe OHSS can be virtually eliminated,” he said.
ALTERNATIVE SOURCES FOR OOCYTES
Given that there is always going to be some potential risk to egg donation, it makes sense to look for alternate sources of eggs—sources that do not rely on the traditional process of ovary stimulation and surgical retrieval that was developed for in vitro fertilization. The workshop participants discussed several of these alternatives.
One possibility, as Dr. Guzick pointed out, is to take advantage of an existing resource—that is, couples who have undergone IVF and who may have embryos they don’t wish to use themselves and which might be available for donation. At this point, no one really knows how many such embryos there are, but it should be worth looking into.
Catherine Racowsky, associate professor of obstetrics, gynecology, and reproductive biology at Harvard Medical School, brought up a second alternative. “In a typical IVF cycle,” she said, “only about 80 percent of the eggs are mature. Of the remaining 20 percent, some of them are