The effect of the duration of GnRH-agonist down regulation before ovarian stimulation on the biological and clinical outcome after intracytoplasmic sperm injection.

The object of this study was to compare the biological outcome (oocyte maturity, fertilization, cleavage) and the clinical outcome after a 'long' (15-24 days) and a 'long-long' (25-40 days) protocol of GnRH-agonist administration for intracytoplasmic sperm injection. Group A consisted of 51 patients with a 15-24-day down regulation period and Group B consisted of 35 patients with a 25-40-day down regulation period, all of which entered ICSI due to severe male factor infertility. Duration and amount of gonadotropin stimulation, serum E2 on the day of hCG administration, number of oocytes retrieved, oocyte maturity, fertilization rate, cleavage rate and pregnancy outcome were comparable for the two groups of patients. Therefore, a flexible period of pituitary desensitization can be employed, allowing us to simplify planning for patients and for the medical staff without affecting the outcome of the trial.