OBJECTIVE: To assess the efficacy of oocyte donation when a cohort of oocytes is shared between two phenotypically matched recipients. DESIGN: A retrospective analysis of a program using shared anonymous oocyte donation. SETTING: Academic infertility center. PATIENT(S): Recipient women with partial or complete ovarian failure; oocyte donors who have been properly screened. INTERVENTION(S): Each oocyte donor was phenotypically matched with two potential recipients. The cohort of donated oocytes were divided between these two recipients if eight or more mature oocytes were obtained at retrieval. Recipients underwent hormone replacement therapy consisting of down-regulation with a GnRH agonist, transdermal estradiol, and intramuscular progesterone in a dose determined by a previous preparatory cycle. MAIN OUTCOME MEASURE(S): Pregnancy and delivery rates for all transfers originating from a cohort of oocytes obtained by retrieval of a single donor; pregnancy and delivery rates per recipient; rate of conversion of a shared donation cycle to a single recipient. RESULT(S): A total of 249 donor cycles permitted 241 retrievals. Each recipient received 8.3 +/- 3.5 oocytes per donation. There were 424 fresh ETs and 48 frozen ETs performed. For fresh ETs, clinical pregnancy and ongoing or delivery rates per recipient were 56.8% and 49.7%, respectively. For frozen ETs, these rates were 50% and 39.5%. Implantation rates were 31.8% and 26.1% for fresh and frozen ET, respectively. When analyzed per donor retrieval, clinical pregnancy and ongoing or delivery rates were 109.5% and 95.4%. These high pregnancy rates per donor reflect the numerous fresh and frozen ETs that can result from one donor's retrieval. Conversion of a donation cycle from two recipients to one recipient occurred for 26 of 241 cycles (10.8%). CONCLUSION(S): Shared anonymous oocyte donation provides a very high pregnancy rate per donor retrieval that is not achievable with unshared donation. In addition, there is a diminished risk exposure of donors per total completed recipient transfers. We support shared oocyte donation as the most efficient use of the precious resource of human oocytes.
