Fixed versus flexible gonadotropin-releasing hormone antagonist administration in in vitro fertilization: a randomized controlled trial

ObjectiveTo evaluate whether the incidence of luteinizing hormone (LH) rise is reduced by using a flexible compared with a fixed day-6 protocol of GnRH antagonist administration.DesignRandomized controlled trial.SettingTertiary university hospital.Patient(s)Patients undergoing in vitro fertilization (n = 146).Intervention(s)Ovarian stimulation was performed using recombinant FSH and GnRH antagonists. GnRH antagonist cetrorelix (0.25 mg/d) was started either on day 6 of stimulation (fixed group) or when LH was >10 IU/L, and/or a follicle with mean diameter >12 mm was present, and/or serum E2 was >150 pg/mL. Patient monitoring was initiated on day 3 of stimulation.Main Outcome Measure(s)Incidence of LH rise.Result(s)No statistically significant difference was observed between the flexible and fixed groups regarding the incidence of LH rise, which was lower in the flexible group (11.0% vs. 15.1%, difference −4.1%, 95% confidence interval −15.4% to +7.1%). No LH surges were observed in any of the patients studied.Conclusion(s)Flexible antagonist administration from day 3 onward does not appear to reduce the incidence of LH rises compared with fixed antagonist administration on day 6 of stimulation.