Evaluation and treatment of low responders in assisted reproductive technology: A challenge to meet

Purpose: To investigate the various methods of evaluation and treatment of patients with a low response to controlled ovarian hyperstimulation in assi sted reproductive technologies (ART). Methods: Review and analysis of relevant studies published in the last deca de, identified through the literature and Medline searches. Results: While a universally accepted definition for low responders is stil l lacking, these patients are reported to represent about 10% of the ART po pulation. Several ovarian reserve screening techniques have been proposed; however currently the best-characterized and most sensitive screening tools available are the basal day 3 serum follicle-stimulating hormone level and the clomiphene citrate challenge rest. When abnormal, these tests allow ph ysicians to counsel patients that their prognosis for conception is pool: A lthough the presence of a normal result does indicate better long-term chan ces for conception, an age-related decline in fecundity remains and patient age should still be considered when counseling patients with normal screen ing results. Several stimulation protocols have been applied in the low-res ponse group with varying success. Recent studies show that the use of a min idose gonadotropin-releasing hormone-agonist protocol may result in signifi cantly decreased cycle cancellations as well as increased clinical and ongo ing pregnancies and thus is proposed as a first-line therapy Studies evalua ting supplementary forms of treatment to the ovulation induction regimen sh ow improved outcome when pretreating with oral contraceptives. whereas ther e seems to be no benefit from cotreatment with growth hormone or glucocorti coids. Blastocyst culture and transfer and assisted hatching in low respond ers are still under evaluation, whereas natural cycle in vitro fertilizatio n may be used in cases of repeated failures as a last option before resorti ng to oocyte donation or adoption. Future possible forms of treatment like in vitro maturation of immature human oocytes, cytoplasm, and nuclear trans fer currently are experimental in nature and their efficacy has still to be proven. Conclusions: The evaluation and treatment of low responders in ART remains a challenge. Understanding of the underlying etiology and pathophysiology o f this disorder may help the clinician to approach it successfully.