Effects of pretreatment with an oral contraceptive on the time required to achieve pituitary suppression with gonadotropin-releasing hormone analogues and on subsequent implantation and pregnancy rates

Objective: To assess the effect of pretreatment with an oral contraceptive (OC) on ovarian cyst formation during pituitary suppression with buserelin acetate. Design: Prospective randomized trial. Setting: Academic medical center. Patient(s): Eighty-three patients who were undergoing IVF-ET treatment. Intervention(s): Patients in the study group were pretreated with an OC for 14 days starting on the first day of menstruation. The administration of SC buserelin acetate was initiated on the last day of OC administration. Patients in the control group began to receive buserelin acetate on day 2 of menstruation. Hormonal assays and ultrasound scans were performed on the first day of menstruation, and 7, 11, and 14 days after the commencement of buserelin acetate administration. Thereafter, these tests were performed weekly until pituitary suppression was achieved. Main Outcome Measure(s): Incidence of cyst formation. Result(s): A cyst developed in 27 patients in the control group (52.9%) and no patients in the study group (odds ratio [OR] = 115; 95% confidence interval [CI] = 10-617). Patients in the study group achieved pituitary suppression faster (median difference [MD] = 7 days; 95% CI = 4-14) and required fewer ampules of gonadotropin (MD = 10; 95% CI = 6-14). They recruited more follicles (MD = 3; 95% CI = 0-5) and had higher pregnancy rates (37.2% versus 33.3%). Conclusion(s): Pretreatment with an OC abolishes ovarian cyst formation, shortens the time required to achieve pituitary suppression, and decreases gonadotropin requirements without having a negative effect on pregnancy rates. (Fertil Steril(R) 1998;70.1063-9. (C) 1998 by American Society for Reproductive Medicine.)