Empty follicle syndrome prevalence and management in oocyte donors

STUDY QUESTION: Is the drug used for final oocyte maturation a factor in determining the prevalence of empty follicle syndrome (EFS)? SUMMARY ANSWER: The drug used for final oocyte maturation is not a factor in determining the prevalence of EFS among women unaffected by infertility. WHAT IS KNOWN ALREADY: Despite satisfactory follicular stimulation and adequate follicular development, cases of EFS, i.e. failure to recover any cumulus oocyte complex, have been reported both with hCG and GnRH agonist triggering. No standard management protocol has been proposed so far. STUDY DESIGN, SIZE, DURATION: Retrospective analysis of oocyte donation cycles performed between August 2006 and April 2013 in a large private fertility centre. PARTICIPANTS/MATERIALS, SETTING, METHODS: The analysis included 12 483 oocyte donation cycles of which 74 were EFS cycles. All cycles were triggered with either hCG or GnRH agonists. MAIN RESULTS AND THE ROLE OF CHANCE: There were no differences in the gonadotropic stimulation, pituitary suppression and triggering drug between cycles where oocytes were recovered successfully and EFS cycles. The total prevalence of EFS was 0.59%. Given the rarity of the syndrome, caution is advised when interpreting the analysis. LIMITATIONS, REASONS FOR CAUTION: The main limitation of this study is its retrospective nature. Although this is the largest analysis of EFS in donors reported so far, its statistical power is limited because the syndrome has a low incidence. In some cycles of EFS from 2006 to 2007 there is a lack of hormone data. WIDER IMPLICATIONS OF THE FINDINGS: Our findings may be generalized to oocyte donors and IVF patients younger than 35 years old, with cycles undergoing final maturation triggering with either hCG or GnRH agonists. The generalization cannot be extended to patients with an ovarian factor as the cause of their reproductive pathology. The theoretical aetiology of a temporary hypothalamic-pituitary hyposensitivity can explain the cycles where a rescue protocol with hCG has been successful. STUDY FUNDING/COMPETING INTEREST(S): This work was supported in part by funding from Fundacio EUGIN. The authors have no conflicts to declare. TRIAL REGISTRATION NUMBER: NA.