Prevalence, Definition, and Classification of Infertility

Abstract

Infertility, defined by the World Health Organization as “a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse,” is considered by experts in the field to be a problem that affects 15–20 % of couples. Another fact on which there is substantial convergence of views is that a male cause is present in about 50 % of cases. These data, however, are questionable and not measurable in a direct way, although several indirect methods have been used. In fact, in most cases of couple infertility the presence of a male factor is established on the basis of the seminal data, that is, on laboratory data characterized by a high coefficient of variability. In addition, time to pregnancy, a parameter that can identify cases of a couple’s subfecundity, has been shown to correlate with sperm quality and quantity, sexual activity, and a number of other conditions. The current trend to refer the infertile couple to in vitro fertilization programs without a comprehensive male evaluation reduces the possibility of understanding the real impact of male infertility, namely his biological incapacity to reproduce, on the function of a couple-based concept such as fertility.