Administration of a gonadotropin-releasing hormone antagonist during the 3 days before the initiation of the in vitro fertilization/intracytoplasmic sperm injection treatment cycle: impact on ovarian stimulation. A pilot study.

To investigate the impact on the number of cumulus-oocyte complexes (COC) when a 3-day course of GnRH antagonist treatment precedes the initiation of controlled ovarian stimulation with gonadotropins in a GnRH antagonist protocol for IVF/intracytoplasmic sperm injection (ICSI).Randomized controlled trial.Tertiary referral center.Sixty-nine women undergoing controlled ovarian hyperstimulation for IVF/ICSI.The control group (n = 36) received a standard treatment with daily injections of recombinant FSH (rFSH), starting on day 2 of the cycle at a dose of 150-225 IU/day, and GnRH antagonists from cycle day 7 onward. In the pretreatment group (n = 33), a GnRH antagonist was administered from day 2 of the menstrual cycle onward during 3 consecutive days; thereafter controlled ovarian stimulation was initiated with the same protocol as used in the control group.The primary endpoint was the number of COCs at egg retrieval.Both groups had comparable baseline characteristics. The duration of rFSH stimulation and consumption of gonadotropins were similar in both groups. The number of COCs was higher in the pretreatment group (12.8; SD, 7.8) compared with in the control group (9.9; SD, 4.9), although this increment was not significant (between-group difference of 2.9 [95% confidence interval {CI} -0.2 to 6.0]). The ongoing pregnancy rates per started cycle of 14/33 (42%) versus 12/36 (33%) for pretreatment versus control did not differ significantly (between-group difference, 9.1%; 95% CI, -13% to 30%).Among women under 36 years old, early follicular phase GnRH antagonist pretreatment in a fixed GnRH antagonist protocol results in a trend toward a higher number of retrieved oocytes but does not yield significantly higher pregnancy rates.