Prospective randomized study of D-Trp6-LHRH versus buserelin in long desensitization protocols for medically assisted conception cycles. 
In a prospective, controlled, randomized study where two different agonists were used, we compared three different long desensitization protocols for induction of multiple follicular growth in medically assisted conception cycles.  In protocol A, 30 patients were injected with buserelin twice a day for 15 days prior to ovarian stimulation until human chorionic gonadotrophin (HCG) administration.  In protocol B, 30 patients were injected with a single dose of long acting Triptorelin (3.75 mg) 15 days before the ovarian stimulation onset.  In protocol C, 30 patients were injected with the long acting Triptorelin 4 weeks before ovarian stimulation followed by daily administration of 0.1 mg of the same agonist until HCG injection.  There was no difference in the ovarian response to exogenous gonadotrophin stimulation, except for the presence of premature luteinization in two patients in group B. A significantly higher number of mature oocytes was collected from patients with protocol A; however, the fertilization and cleavage rate demonstrated no significant difference among the three groups of patients.  The ongoing pregnancy rate and the implantation rate per treatment cycle were very similar in the three study groups.  When the convenience, cost and side-effects for the patient are being considered, protocol B should be selected as the first choice when the agonist is utilized for the purpose of inducing pituitary desensitization before and during ovarian stimulation.