Pretreatment with an oral contraceptive is effective in reducing the incidence of functional ovarian cyst formation during pituitary suppression by gonadotropin-releasing hormone analogues

Purpose: Our purpose was to assess the effect of pretreatment with oral con traceptives (OCs) on the formation of functional ovarian cysts during pitui tary supression with gonadotropin-releasing hormone (GnRH) agonists, subseq uent follicular development, and pregnancy rates. Methods: A retrospective case-controlled study of 31 in vitro fertilization (IVF) patients, all of whom in a previous cycle had commenced the long pro tocol of GnRH-agonist (Buserelin) in the early follicular phase and were pr etreated in a subsequent cycle with 2 weeks of an OC containing 30 mu g of ethinyl estradiol and 150 mu g of desogestrel prior to GnRH-agonist adminis tration, was undertaken. Follow-up visits were arranged after a minimum of II days of GnRH-agonist administration and weekly thereafter until pituitar y suppression was achieved. Results: Cysts were detected in 16(51.6%) of the 31 patients not pretreated with OCs, and in 0 (0%) of the 31 patients pretreated with OCs (odds ratio = 67.1; 95% confidence interval = 5.6-350.7). Patients pretreated with OCs achieved pituitary suppression more rapidly (median difference = 4 days; 9 5% confidence interval = 2-7) and had comparable gonadotropin requirements and pregnancy rates. Conclusions: Pretreatment with OCs prior to pituitary suppression in the ea rly follicular phase decreases ovarian cyst formation, without an apparent effect on subsequent follicular recruitment or pregnancy rates.