A FLEXIBLE PROTOCOL FOR THE INDUCTION OF RECIPIENT ENDOMETRIAL CYCLESIN AN OOCYTE DONATION PROGRAM

Synchronization of the availability of good quality oocytes from donor s and adequate endometrial maturation of recipients are very important for the success of an oocyte donation programme. A flexible protocol for the endometrial preparation of recipients is important in timing e mbryo transfer between days 17 and 19 of the cycle ('window of recepti vity'), The purpose of this study was to evaluate the effect of the le ngth of oestradiol administration to recipients on pregnancy outcome, Oestrogen administration was 8 mg/day, but its length varied prospecti vely from 6 to 27 days, followed by the addition of progesterone (100 mg daily i.m.) for 2-4 days according to the availability of good qual ity oocytes. Pregnancy outcome was evaluated regardless of age, indica tion for oocyte donation or number of embryos transferred per patient, The pregnancy rate per cycle was comparable when oestradiol was admin istered from 6 to 11 days before progesterone addition, while it dropp ed significantly thereafter, The variation in progesterone administrat ion did not affect pregnancy outcome, These findings provide us with a greater flexibility by allowing us to vary oestradiol administration to recipients from 6 to 11 days prior to progesterone, reducing consid erably, therefore, the need to cancel embryo transfer because of oocyt e unavailability, Thus we can arrange to transfer embryos between days 17 and 19 of the recipient's cycle so as to obtain the best possible clinical outcome.