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Assessing the Medical Risks of Human Oocyte Donation for Stem Cell Research: Workshop Report
anesthesia during oocyte retrieval, he found that such complications as intubation or desaturation—a lowering of the blood oxygen content—were infrequent, but they were more likely in obese patients. Approximately 8 percent of the obese patients experienced desaturation, compared with less than 1 percent of those of normal weight. And 1.7 percent of obese patients required intubation versus 0.1 percent of patients of normal weight.
The bottom line, Dr. Tsen said, is that the potential risks of anesthesia for oocyte retrieval are very low—rare mortality, rare major morbidity, and rare minor morbidity. The one potential risk factor that applies to egg donors and that might put them at more risk during anesthesia is if they are obese, but even then the potential risks remain very small.
POTENTIAL LONG-TERM EFFECTS ON FERTILITY
The final question concerning the potential risks of oocyte retrieval is the surgery’s implications for a woman’s future fertility. Is her ability to have children in the future threatened in any way by having had this surgery? Nicholas Cataldo, formerly an assistant professor of obstetrics and gynecology at Stanford University, reviewed the evidence bearing on this question for the workshop.
Dr. Cataldo examined two possible pathways by which oocyte retrieval might conceivably affect future fertility. The first pathway begins with the infection and bleeding that, as described above, are occasional side effects of retrieval surgery. These side effects sometimes lead to the need for surgery or to the formation of adhesions, the sticking-together of two adjacent tissues. Both of these results, Dr. Cataldo said, could theoretically lead to fertility problems.
There is little evidence to support this possibility, however. According to one large study, the rate of infection after oocyte retrieval was about 1 in every 200 IVF cycles, and surgery is needed to treat pelvic abscesses in less than 1 in 1,000 IVF cycles. Furthermore, since women have a set of two ovaries and two fallopian tubes, they can remain fertile even if one set is damaged, and there is no evidence that both might be threatened simultaneously by the side effects of retrieval surgery. In one study that examined this particular issue, Dr. Cataldo said, none of the women who had surgery to treat abscesses had them on both sides or lost both fallopian tubes or ovaries. As for adhesions, research has not found a higher rate of adhesions among women who have undergone oocyte