Oocytes obtained from unstimulated ovaries can be used for oocyte donation and the pregnancy rates are comparable to those seen with conventional oocyte donation, new research suggests.
According to the report, which appears in the July issue of
Fertility and Sterility, there is currently a shortage of oocyte donors, which may, in part, relate to side effects associated with the stimulation protocol employed. The goal of the present study was to determine if oocytes obtained from unstimulated ovaries and then maturated in vitro could be suitable for donation.
The study involved 12 oocyte donors with ultrasound-only polycystic ovaries or polycystic ovary syndrome, who were matched with 12 oocyte recipients. Following oocyte maturation, fertilization and then embryo transfer occurred.
On average, 12.8 germinal-vesicle oocytes were obtained per collection, lead author Dr. Hananel Holzer, from McGill University in Montreal, and colleagues note. With a maturation rate of 68.3 per cent, the average number of mature oocytes per collection was 8.7.
Roughly 73 per cent of fertilization attempts were successful, the report indicates. A median of four embryos were transferred.
Six of the recipients conceived, yielding a clinical pregnancy rate of 50 per cent per cycle. The average implantation rate per embryo and the live birth rate per cycle were 18.2 and 30 per cent, respectively.
"Collecting immature oocytes from unstimulated ovaries for the purpose of oocyte donation is a simple procedure that totally avoids ovarian stimulation," the authors conclude.
"With appropriate selection of women with ultrasound-only polycystic ovaries or women with the polycystic ovary syndrome, the pregnancy rates of the recipients are comparable with those achieved through conventional in vitro fertilization oocyte donor cycles.
