DEBATE The Bologna criteria for poor ovarian response: the good, the bad and the way forward

abstract: Themanagement of poorovarian response (POR) remains oneof themost significant challengesof in vitro fertilization.Numerous interventions havebeenproposed, yet fewhavebeen shown tobebeneficial. Themost important problem in evaluating the available evidencehas been the lack of a standardized definition of POR. The Bologna criteria for POR have been recently introduced to provide a framework allowing future research in this field tobeperformedona relatively homogenouspopulation.However, it has been suggested that thepopulationdescribed by the Bologna criteria might not be sufficiently homogenous and for this reason stratified randomization should be used in relevant randomized controlled trials (RCTs). Stratified randomization, besides its advantages, also has important shortcomings and for this reason it should be used onlywhen there is clear evidencemandating such a design. Currently, there is insufficient data to support such practice in RCTs performed on the population described by the Bologna criteria for POR. Until such evidence becomes available, the scientific community should aim at evaluating interventions for POR according to the Bologna criteria in RCTs of sufficient sample size, with proper allocation concealment and masking. Key words: ovarian stimulation / randomized controlled trials / poor ovarian respons