Poor responders in IVF--is there any evidence-based treatment for them?

Despite the vast experience in controlled ovarian hyperstimulation, there are still women who respond poorly to gonadotropins, which results in few oocytes at retrieval, reduced number of embryos for transfer and consequently unsatisfactory pregnancy rates. Although such patients are quite common in IVF practice, the exact prevalence of so-called "poor responders" is difficult to estimate due to the variety of applied definitions. The urgent need for an internationally accepted definition of poor ovarian response (POR) was addressed by an ESHRE Workshop held in Bologna in 2010, where the consensus was reached and criteria were finally established. The application of this uniform definition may allow a correct estimate of POR prevalence and, what is more important, designing proper trials to assess and finally compare the interventions used in POR patients. The article describes the possible physiology of POR and patient characteristics, mentions risk factors and laboratory tests of decreased ovarian reserve. Finally it reviews the possible management of POR with different stimulation protocols in the light of EBM. Basing on published meta-analyses, various additional alternatives (such as estradiol priming, the addition of rLH, growth hormone, androgens and androgen-modulating agents, aspirin) are also summarized. Despite the two decades of trying, there is still no consensus on what is best for POR. No single treatment can be recommended over another, as the evidence for all of them is insufficient. It is obvious that interventions used in POR require properly designed large randomized studies, because until now there is no evidence-based treatment for that particular group of patients.