OUTCOME OF FROZEN EMBRYO REPLACEMENT CYCLES FOLLOWING ELECTIVE CRYOPRESERVATION OF ALL EMBRYOS IN WOMEN AT RISK OF DEVELOPING OVARIAN HYPERSTIMULATION SYNDROME

Aim: Our aim was to compare the outcome in subsequent frozen embryo re placement cycles in four groups of patients who had elective cryoprese rvation of all their embryos because they were considered to be at inc reased risk of developing severe ovarian hyperstimulation syndrome. De sign: Sixty-two (91%) of 68 NF cycles (68 patients) in which elective cryopreservation of all embryos was performed were analyzed All patien ts continued on the GnRH agonist, buserelin, after oocyte recovery unt il the onset of vaginal bleeding. Frozen embryo replacement occurred i n a hormone replacement cycle that started either on day 3 of the with drawal bleed (group I; N = 15) or after serum estradiol levels had fal len to <100 pmol/L (group II; N = 16). The other patients commenced a frozen embryo replacement cycle several months later in either a hormo ne replacement (group III; N = 15) or a natural (group IV; N = 16) cyc le. Results: Two patients developed severe ovarian hyperstimulation sy ndrome, There were no significant differences among the four groups re garding demographic variables, the dose of hMG used, and the clinical outcome. There was a higher but not significantly different clinical p regnancy rare in group I (26.7%), compared to group II (12.5%), group III (13.3%), and group IV (18.8%). Conclusions: Several options exist for the timing and protocol used for frozen embryo replacement in pati ents who had elective cryopreservation for the prevention of ovarian h yperstimulation syndrome, none of which was found to be clearly superi or in this observational report.