[Comparison of different protocols of ovulation induction, by GnRH agonists and chorionic gonadotropin].

OBJECTIVE: The aim of this study was to determine the best way of using a gonadotropin-releasing hormone agonist (GnRHa) for triggering ovulation and to analyse the reasons for short luteal phases.

MATERIALS AND METHODS: Thirteen different regimens of GnRH-a administration were used to trigger ovulation using different dosages and either one, two or three administrations: triptorelin, buserelin spray, buserelin subcutaneously, leuprolide and nafarelin in 231 treatment cycles. Pregnancy rate and luteal phase duration were compared with those of a control group for whom ovulation was triggered with hCG.

RESULTS: Ovulation with supraphysiologic elevation of both FSH and LH was achieved in the 13 GnRHa groups. For the five main groups analysed, GnRHa produced shorter and inadequate luteal phases than did hCG but no difference was found between agonists. Pregnancy rates were not statistically different between the agonist groups or in comparison with the hCG group.

CONCLUSION: The use of GnRHa to trigger ovulation is efficient, despite short luteal phases, and has proven its utility in comparison with hCG. As the different modes of stimulation appear to yield comparable results, the cost of treatment should be a significant element to take into consideration.