Relationship of timing of agonist administration in the cycle phase to the ovarian response to gonadotropins in the long down-regulation protocols for assisted reproductive technologies

Objective: To assess whether the ovarian response to exogenous gonadotropins and cycle performance is affected by different timing of an agonist administration in long down-regulation protocols. Design: An agonist was administered irrespective of cycle phase, with exogenous gonadotropin beginning 15 days later. Patients: Five hundred fifty-seven normovulatory infertile patients, aged less than or equal to 38 years, were classified into seven study groups, depending on the phase of the cycle in which agonist was started. Main Outcome Measures: Endocrine profile, amount of exogenous stimulation, occurrence of ovarian cysts, mean number of oocytes recovered and embryos transferred, pregnancy rate, implantation rate, and live-birth rate of the seven groups. Results: The ovarian response of the groups did not show any statistically significant differences in relation to the initiation of the agonist. The only effect was a different incidence of ovarian cyst formation, but this phenomenon did not affect cycle performance. The pregnancy, implantation, and live-birth rates showed differences that did not reach statistical, significance. Conclusion: Agonists initiation can be programmed in advance irrespective of the phase of the cycle. This approach can be of help for the logistics of assisted reproduction programs.