Empty follicular syndrome: incidence in 2729 IVF cycles and prognosis in subsequent attempts

Abstract

Introduction: The empty follicle syndrome (EFS) is described as the failure to retrieve oocytes at ovum pick-up (OPU) after an adequate controlled ovarian stimulation (COS) in patients undergoing in vitro fertilization (IVF). Objectives: To retrospectively calculate the incidence of EFS in IVF cycles and to assess the prognosis of these patients in subsequent IVF attempts. Patient(s): Women undergoing 2729 IVF cycles of homologous IVF at our IVF Unit in the years 2010-2014. Intervention(s): All cases with no retrieved oocytes at OPU were considered and divided into two sub-categories: (a) genuine EFS (gEFS), when a correct ovulation trigger was performed; and (b) false or iatrogenic EFS (iEFS), when no urinary hCG was detected the day of OPU, indicating a mistake in the administration of exogenous hCG for triggering. Main Outcome Measure(s): We calculated the incidence of EFS and then analyzed the outcome of subsequent IVF cycles in the same patients. Result(s): Eighty cases of EFS were identified in 2729 cycles (overall incidence 2.9%). Among EFS cases, 88% were gEFS and 11% were iEFS. The incidence of EFS was higher among patients above 40 years than in younger women (6.26% vs. 1.81%) (Table 1). Twenty-nine patients with gEFS underwent subsequent IVF cycles, and oocytes were retrieved in 88.6% of them, leading to a pregnancy rate/cycle of 20%, with no relevant differences according to age (PR/cycle 16.6% in younger women, 23.5% in women older than 40) (Table 1). Conclusion(s): We observed that EFS has an overall low prevalence among women undergoing IVF, but its incidence is five-times higher after 40 years of age, involving mainly patients with a low ovarian reserve. The iatrogenic form of EFS, iEFS, can be easily identified by testing hCG levels in urine samples the day of OPU, and occurs independently from age. Patients who experienced gEFS in an IVF attempt had a high chance of retrieving eggs in the subsequent IVF cycle and an acceptable pregnancy rate; interestingly, age did not negatively affect their prognosis.