FSH treatment of male idiopathic infertility: Time for a paradigm change.

Follicle-stimulating hormone (FSH) has been used in inconclusive clinical trials for male idiopathic infertility in the past. FSH is sometimes prescribed empirically for male idiopathic infertility, showing some improvement in sperm parameters in about half of the patients. In this opinion article, we briefly analyze the pathophysiological evidences in favor of a more aggressive approach in planning future studies on pharmacological FSH use in male infertility, in analogy with the FSH use for multiple follicular growth in women undergoing ovarian stimulation for assisted reproduction. There is sufficient evidence that spermatogenesis does not run at its top in the primate and that some extra FSH can stimulate spermatogenesis over its baseline. Existing data suggest that the pharmacological regimens applied so far were insufficient, both in dosage and in duration, to elicit this response in about half of the patients. A paradigm change is needed now: We should move away from the classical, endocrinological approach, which simply applied the substitutive, therapeutic regimen used in hypogonadotropic hypogonadism, toward testing a 'testicular hyperstimulation' scheme for a time sufficient to cover more than only one spermatogenic cycle, a concept to be verified in an appropriately controlled, prospective, randomized clinical trial.