completely immature, and some of them are partially mature.” At this point, in a typical IVF labs, those immature and partially mature eggs are discarded, but researchers are working on ways to mature such eggs in vitro, so that they can be recovered and used. If these techniques can be perfected, this would be a way to increase the supply of eggs without the need for more donors.
On a related note, Dr. Cataldo pointed out that techniques are being developed to mature eggs in vitro after only a very brief exposure to hormones, primarily hCG. This could greatly increase the potential donor pool. For example, in women who have a number of small antral follicles, it might be possible to retrieve a significant number of oocytes without putting the woman through the usual ovarian stimulation. Clinical studies have already shown that these oocytes can be successfully fertilized after being matured in vitro, Dr. Cataldo said. So women who might otherwise be excluded from donating their eggs for research—such as women with polycystic-appearing ovaries—could in this way provide eggs without the potential risks that would accompany such a donation done via the usual path.
Finally, there was some discussion about the possibility of retrieving oocytes from cadavers in much the same way that organs are now retrieved from the bodies of people who have signed organ donation cards. As Dr. Giudice put it, in addition to donating your organs to science you might want to donate your gametes.
For that to become a reality, it would be necessary to be able to store oocytes from cadavers in such a way that they remain viable until they can be used. At this time, Dr. Racowsky said, medical researchers are working to perfect the technique of oocyte freezing. “Some programs are having really quite good success rates with egg freezing now,” she said, “but it’s not universally the case. With a little bit more experience and technological advances, hopefully in the near future we’ll have that also as a useful tool to be able to store very valuable material for this work.” If so, it should open up one more alternative source of oocytes.
For now and for at least the near future, however, the major source of oocytes for research is likely to remain eggs donated by women specifically for use in research.