Comparison of leuprolide acetate and human chorionic gonadotropin for the induction of ovulation in clomiphene citrate-stimulated cycles

Objective: To examine the relative efficacies of leuprolide acetate (LA) and hCG in inducing ovulation and a normal luteal phase during clomiphene citrate (CC)-stimulated superovulation cycles. Design: Prospective, randomized, blinded, and cross-controlled in consecutive cycles. Setting: Large military tertiary care center. Patients: Twenty-one ovulatory patients undergoing superovulation with CC and IUIs for the treatment of unexplained or male factor infertility. Interventions: Clomiphene citrate (100 mg/d) on cycle days 5 through 9 in both of the study cycles. Administration of 2 mg SC LA in one cycle and 10,000 IU IM hCG in another cycle for induction of the midcycle surge. Main Outcome Measures: Serum LH, FSH, E₂, and P levels every 12 hours for 36 hours after administration of either LA or hCG to characterize the midcycle hormonal dynamics. Luteal phase duration and serum P levels during the midluteal phase were used to estimate the adequacy of the luteal phase. Serial ultrasounds also were done to determine the incidence of luteinized unruptured follicle syndrome. Results: Serum FSH levels in the periovulatory interval were significantly higher after the administration of LA. There were no differences in the periovulatory E₂ or P levels or the incidence of sonographic evidence of ovulation after administration of either LA or hCG. Although midluteal serum P levels were higher in the cycles in which hCG was administered, all 42 treatment cycles had adequate luteal phases as assessed by luteal phase duration and three midluteal P levels. Ongoing pregnancies occurred after both LA- and hCG-stimulated cycles. Conclusion: Leuprolide acetate and hCG were equivalent in their abilities to induce ovulation. Further evaluation of the adequacy of the luteal phase and the ensuing pregnancy rates after LA induction of an endogenous gonadotropin surge are indicated.