Aim: To determine the incidence of recurrent empty follicle syndrome (EFS) and to analyse the factors associated with this phenomenon. Methods: Retrospective analysis comparing all EFS cycles with cycles in which oocytes were retrieved in our in vitro fertilization (IVF) unit between 1998 and 2006. Results: Of 8292 IVF cycles, 163 (2.0%) resulted in empty follicles. Risk factors for EFS included advanced age (37.7±6.0 years vs. 34.2±6.0 years, p<0.001), longer infertility (8.8±10.6 years vs. 6.3±8.4 years, p<0.05), higher baseline follicle-stimulating hormone levels (8.7±4.7 IU/L vs. 6.7±2.9 IU/L, p<0.001) and lower E2 levels before the human chorionic gonadotropin injection (499.9±480.9 pg/mL vs. 1516.3±887.5 pg/mL, p<0.001) compared with cases in which ova were retrieved. Among patients with EFS, recurrent EFSs occurred in 15.8% of subsequent cycles. Conclusion: The EFS is a sporadic event in the majority of patients. However, in about 16% of the patients, EFS may recur. These cases may be a variant form of poor response and patients with repetitive EFS syndrome should be counseled concerning their chances to conceive.
- Empty follicle syndrome
- Stimulated cycles