The pregnancy rate was found to be higher when GnRHa was used in a long protocol as compared to a short or ultrashort protocol. There was no evidence of a difference in live birth rate, but this outcome was only reported by three studies. There was no evidence of a difference in the outcomes amongst various long protocols; nor that stopping or reducing GnRHa at the start of stimulation was associated with a reduced pregnancy rate. For all comparison, except a long versus short protocol, there was a lack of power.
Prospective study of short and long regimens of gonadotropin-releasing hormone agonist in in vitro fertilization program.
To assess the usefulness of a short regimen in ovulation induction in an in vitro fertilization (IVF) program.
                A prospective randomized trial was set up to compare long and short regimens of gonadotropin-releasing hormone agonist administration for ovulation induction in IVF.
                Aberdeen Assisted Reproduction Unit.
                Eighty-seven patients undergoing IVF were randomized between the two protocols. Stimulation regimen was the only variable being tested.
                Stimulation response and occurrence of luteinizing hormone (LH) surges.
                There was no difference in the stimulation requirements, response to stimulation, number of follicles aspirated, or the number of oocytes obtained. The fertilization rates, number of embryos transferred, and pregnancy rates were also similar in both groups. Like the long regimen, it prevents the occurrence of a premature LH surge.
                The short regimen is a useful and cheaper alternative in ovarian stimulation of patients undergoing IVF.