A shared egg donor program: which is the minimum number of oocytes to be allocated?

Purpose To evaluate which is the minimum number of oocytes to be allocated to each recipient in a shared egg donor program. Methods We analyzed 953 recipients that received at least 4 metaphase II (MII) oocytes in the period 2006-2008. We retrospectively divided the recipients according to the number of MII oocytes actually received. Results No statistically significant differences were found among the analyzed strata in clinical pregnancy rate (A:43.7%; B:45.6%; C:48.6%; D:45.5%; E:53%, P=NS) and miscarriage rate. However, the rate of top quality transferred embryos, and the embryo freezing rate were significantly higher among those recipients that received 7 or more mature eggs. Conclusions After a large sample was analyzed, no significant differences in fresh embryo transfer outcome were encountered when a different number of oocytes was allocated. A minimum of 4 MII oocytes seems to achieve satisfactory pregnancy rates in our shared egg donor program.