Performance of cryopreserved pre-embryos obtained in in vitro fertilization cycles with or without a gonadotropin-releasing hormone agonist.

OBJECTIVE: To evaluate the viability and potential for pregnancy of cryopreserved/thawed pre-embryos obtained after ovarian stimulation using gonadotropin-releasing hormone agonist (GnRH-a) adjunct therapy. DESIGN: Retrospective clinical evaluation of all patients receiving a gonadotropin ovarian stimulation protocol (follicle-stimulating hormone/human menopausal gonadotropin FSH/hMG]) with/without GnRH-a. SETTING: Academic tertiary clinical care unit. PATIENTS: Patients receiving leuprolide acetate (LA)/FSH/hMG (n = 136: LA in the luteal phase; long protocol) were compared with patients receiving FSH/hMG alone (n = 130) within the same time-frame in our program (April 1987 through October 1989). INTERVENTIONS: All patients had both a cycle in which pre-embryos were transferred fresh and a cycle of thaw of cryopreserved pre-embryos (frozen at the pronuclear stage in a slow freeze-thaw protocol using 1,2 propanediol) transferred in monitored natural cycles. MAIN OUTCOME MEASURES: Groups were similar in age, etiology of infertility, and cycle day 3 serum FSH levels; a significantly higher (P less than 0.001) number of preovulatory oocytes was recovered in the GnRH-a group. Both groups of patients were transferred an equal number of pre-embryos at the time of IVF. Cycles with frozen/thawed pre-embryos were evaluated based on the analysis of the three main variables that demonstrate cryopreservation efficiency: survival rate, implantation rate, and term pregnancy rate (PR). RESULTS: Non-GnRH-a group (113 transfers): pre-embryo survival, 71.5%; PR/transfer, 24.7%; implantation rate, 16.0%; GnRH-a group (125 transfers): pre-embryo survival 71.6%; PR/transfer, 32.8%; implantation rate, 12.0% (no significant differences). CONCLUSIONS: The use of GnRH-a produced pre-embryos of equal aptitude for development after cryopreservation at the pronuclear stage when compared with a similar gonadotropin stimulation treatment without GnRH-a.