A comparative randomized trial to assess the impact of oral contraceptive pretreatment on follicular growth and hormone profiles in GnRH antagonist-treated patients

BACKGROUND: This randomized controlled trial was designed to assess the impact of oral contraceptive (OC) scheduling with a GnRH antagonist ( ganirelix) regimen on the ovarian response of women undergoing recombinant FSH ( rFSH) stimulation for IVF, compared with a non-scheduled ganirelix regimen and a long GnRH agonist (nafarelin) protocol. METHODS: A total of 110 women was treated with an OC and ganirelix, 111 with ganirelix alone and 111 with nafarelin. The OC ( containing 30 mu g ethinylestradiol/150 mu g desogestrel) was taken for 14 - 28 days and stopped 2 days prior to the start of rFSH treatment. Primary efficiency parameters were the number of cumulus-oocyte complexes ( per attempt) and the number of grade 1 or 2 embryos ( per attempt). RESULTS: In terms of follicular growth and hormone profiles, the OC-scheduled antagonist regimen mimicked the agonist regimen rather than the (non- scheduled) GnRH antagonist regimen. In the OC-scheduled GnRH antagonist group and the nafarelin group ( versus the non- scheduled antagonist group), pituitary suppression was more profound at the start of stimulation (P <= 0.001), there was a slower start of follicular growth (P <= 0.001), longer stimulation was required (11.7 and 10.3 days respectively versus 9.4; P <= 0.001), and more rFSH was used (2667 and 2222 IU versus 1966 IU; P <= 0.001). In the three groups, the number of oocytes was similar ( 13.1, 12.9 and 11.5 respectively; not significant) as well as the number of good quality embryos ( 5.1, 5.7 and 5.0 respectively; not significant). CONCLUSION: OC treatment prior to the rFSH/ ganirelix regimen can be successfully applied to schedule patients, although more days of stimulation and more rFSH are required than with a non- scheduled GnRH antagonist regimen.