Delay of gonadotropin stimulation in patients receiving gonadotropin-releasing hormone agonist (GnRH-a) therapy permits increased clinic efficiency and may enhance in vitro fertilization (IVF) pregnancy rates

Objective: To promote an even temporal distribution of patients starting IVF cycles at our center, patients undergoing GnRH agonist (GaRH-a) suppression frequently delay the start of gonadotropin stimulation. Our objective was to analyze the effect that the delay of initiation of gonadotropin stimulation has on outcome parameters in this population. Design: Retrospective analysis. Setting: A tertiary referral reproductive medicine unit. Patient(s): Patients undergoing IVF cycles on long GnRH-a protocols. Intervention(s): Patients were treated with either a ''standard-dose'' or ''low-dose'' leuprolide acetate protocol initiated in the mid-luteal phase, Main Outcome Measure(s): Delay time, clinical pregnancy rate, ongoing pregnancy rate, cancellation rate. Result(s): Analysis of the overall group revealed associations between stimulation delay and decreases in stimulation duration and the number of gonadotropin ampules administered. Weighted linear regression analyzes revealed statistically positive relationships between delay time and both clinical pregnancy rates and ongoing pregnancy rates, despite a positive relationship between delay time and cancellation rates. Analysis of the standard-dose and low-dose subgroups revealed that the enhancement of pregnancy rates was attributable primarily to patients in the standard-dose protocol. Conclusion(s): Delay of gonadotropin stimulation while patients are receiving GnRH-a therapy allows for increased clinic efficiency. There appears to be an enhancement of clinical and ongoing pregnancy rates for the standard-dose leuprolide acetate protocol that is associated with stimulation delay. (C) 1997 by American Society for Reproductive Medicine.