['To evaluate controlled ovarian stimulation cycles using the GnRH antagonist ganirelix in combination with the recombinant FSH, follitropin-beta, in women with polycystic ovary syndrome (PCOS).', 'Prospective, nonrandomized clinical study.', 'Hospital-based infertility practice.', 'Twenty women with PCOS planning to undergo ovarian stimulation.', 'Fasting glucose and insulin levels were used to calculate insulin resistance ratios (FG/I). After pretreatment with oral contraceptives, serum LH levels were determined, and 250 microg ganirelix was administered on cycle day 2. Upon suppression of LH, concurrent ganirelix and follitropin-beta therapy (morning ganirelix and evening follitropin-beta) was started and continued until the day of hCG.', 'Days of stimulation, dose of follitropin-beta, pregnancy, and ongoing pregnancy were compared based on FG/I ratios.', 'One dose of ganirelix effectively suppressed LH levels in all patients. All patients ovulated as documented by a rise in progesterone. Significant differences were observed between the insulin-resistant and non-insulin-resistant groups for both days of stimulation and dose of follitropin-beta. The overall clinical pregnancy rate was 44.4%, with an ongoing pregnancy rate of 27.8%.'] Is concurrent ganirelix and follitropin beta therapy an effective and safe regimen for ovulation induction in women with polycystic ovary syndrome?