Dynamics of the development of multiple follicles during ovarian stimulation for in vitro fertilization using recombinant follicle-stimulating hormone (Puregon) and various doses of the gonadotropin-releasing hormone antagonist ganirelix (Orgalutran/Antagon)

Objective: To investigate relations between dose of GnRH antagonist and follicular phase characteristics. Design: Randomized controlled multicenter trial. Setting: Tertiary referral fertility centers. Patient(s): Three hundred and twenty-nine IVF patients. Intervention(s): Ovarian stimulation for IVF with recombinant FSH starting on cycle day 2. From cycle day 7 onwards, cotreatment was provided with 0.0625, 0.125. 0.25, 0.5, 1.0, or 2.0 mg/d GnRH antagonist. Main Outcome Measure(s): Number of follicles, total follicular surface area, gonadotropin, and serum steroid concentrations. Result(s): In 311 patients, similar follicular growth was observed in all treatment groups. FSH levels increased during the follicular phase. Late follicular phase LH, androstenedione (AD), and E, levels showed a GnRH antagonist dose-related decrease (P<0.05). Late follicular phase E, levels correlated with total follicular surface area, AD, LH, and FSH (all P<0.001), increasing GnRH antagonist doses exhibited additional suppressive action on E, levels. Conclusion(s): Follicular growth was unaffected by the dose of GnRH antagonist. A rise in follicular phase FSH serum concentrations during the follicular phase, largely related to exogenous FSH, enabled ongoing follicular growth in all treatment groups. The effect of GnRH;l antagonist on late follicular phase E, levels could not be exclusively attributed to suppression of LH, (C) 2001 1 by American Society far Reproductive Medicine.