Although most oocyte donation programs provide ovarian stimulation in order to maximize the yield of oocytes, donors may experience mood changes, fatigue, muscle aches, hot flushes, or headaches from the medications administered. In addition, as many as 10% of high-risk women may develop severe ovarian hyperstimulation syndrome. An option is the in vitro maturation (IVM) of oocytes collected from nonstimulated ovaries.
This university-based prospective cohort study was undertaken to determine whether immature oocytes from unstimulated ovaries are a plausible form of donation. Participating were 12 oocyte donors who had more than 20 antral follicles at baseline ultrasonography, preferred to avoid gonadotropins, and underwent 12 oocyte collections in an unstimulated menstrual cycle. Seven of the 12 women in the study had premature ovarian failure. One patient each had responded poorly to ovarian stimulation and had repeated failures of in vitro fertilization (IVF). The remaining 3 women were 47–48 years of age.
A mean of 13 germinal-vesicle oocytes were aspirated in each collection. The IVM rate was 68%, and the mean number of mature oocytes per collection was 8.7. The mean fertilization rate was 73%. From 2 to 5 embryos were transferred; the median number was 4. Six women, half of those in the trial, conceived, for a per-cycle clinical pregnancy rate of 50%. The mean implantation rate was 18%. Two of the 4 patients with a single gestational sac delivered and 2 miscarried. A twin pregnancy resulted in a twin delivery. A woman with a triplet pregnancy chose to have embryo reduction to a singleton pregnancy and this ended in a normal delivery. The 4 live births in this trial translated into a live birth rate of 33% per cycle started.
This experience suggests that pregnancy rates following the collection of immature oocytes from unstimulated ovaries are comparable to those achieved in conventional IVF oocyte donor cycles, and that stimulation-related side effects and costs are avoided. A policy of IVM could attract more prospective oocyte donors and thereby mitigate the difficulties faced by patients awaiting oocyte donation.