The prevalence of genuine empty follicle syndrome

Objective: To describe the prevalence of "genuine" empty follicle syndrome (EFS) and "false" EFS at assisted reproductive technology (ART). Design: Retrospective cohort. Setting: Large private fertility center. Patient(s): A total of 12,359 patients who underwent ART between 2004 and 2009. Intervention(s): None. Main Outcome Measure(s): The failure to recover an oocyte during oocyte retrieval at ART, with and without a detectable serum β-hCG on the day of retrieval. Result(s): Two cases of genuine EFS and nine cases of false EFS were identified in the cohort examined. The prevalence of genuine EFS was 0.016%, and the prevalence of false EFS was 0.072%. Only two out of 11 cases of EFS were considered genuine. Conclusion(s): Genuine EFS is a rare occurrence. Because this syndrome tends to recur with dismal pregnancy rates at ART, continued identification and further investigation of the syndrome are needed.