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 < or = 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.