Beneficial effect of luteal-phase GnRH agonist administration on embryo implantation after ICSI in both GnRH agonist- and antagonist-treated ovarian stimulation cycles.

BACKGROUND GnRH agonist was recently suggested as a novel luteal-phase support that may act at different levels, including the pituitary gonadotrophs, the endometrium and the embryo itself. This prospective randomized study evaluates the effect of GnRH agonist administered in the luteal phase on ICSI outcomes in both GnRH agonist- and GnRH antagonist-treated ovarian stimulation protocols. METHODS Six hundred women about to undergo ovarian stimulation for ICSI (300 using a long GnRH agonist protocol and 300 using a GnRH antagonist protocol) were enrolled in this study. Patients treated with each of these two protocols were randomly assigned to receive a single injection of GnRH agonist or placebo 6 days after ICSI. Implantation and live birth rates were the primary outcomes. RESULTS Administration of 0.1 mg of GnRH agonist triptorelin on day 6 after ICSI led to a significant improvement of implantation and live birth rates after ICSI as compared with placebo. In GnRH antagonist-treated ovarian stimulation cycles, luteal-phase GnRH agonist also increased ongoing pregnancy rate. Moreover, luteal-phase GnRH agonist administration increased luteal-phase serum HCG, estradiol and progesterone concentrations in both ovarian stimulation regimens. CONCLUSIONS Luteal-phase GnRH agonist administration enhances ICSI clinical outcomes after GnRH agonist- and GnRH antagonist-treated ovarian stimulation cycles, possibly by a combination of effects on the embryo and the corpus luteum.