Serum and follicular fluid leptin levels in patients undergoing controlled ovarian hyperstimulation for in vitro fertilization cycle

Objective: To determine serum and follicular fluid leptin levels in patients undergoing controlled ovarian hyperstimulation (COH) for an in vitro fertilization-embryo transfer (IVF-ET) cycle and their possible correlation to COH variables. Setting: Large university-based IVF unit. Patients: 16 consecutive patients undergoing our routine IVF long gonadotrophin-releasing hormone-analog protocol. Interventions and main outcome measures: Blood was drawn three times during the COH cycle: 1) day on which adequate suppression was obtained (Day-S); 2) day of or prior to human chorionic gonadotrophin (hCG) administration (Day-hCG); and 3) day of ovum pick-up (Day-OPU). Levels of sex steroids and serum and follicular fluid leptin were compared among the three time points. Serum leptin was measured with a commercial two-site immunoradiometric assay. Results: Results showed significantly higher levels of serum leptin on Day-OPU and Day-hCG than on Day-S, and significantly higher follicular than serum leptin levels on Day-OPU. Though a significant correlation was observed between serum leptin and body mass index (BMI), no correlations were found between serum or follicular fluid leptin and serum sex-steroid levels or IVF treatment variables. Conclusion: While serum leptin increases during COH for IVF, there is apparently no correlation of serum and follicular leptin levels with sex-steroid levels or IVF outcome.