Definitions and epidemiology of unexplained male infertility

Abstract

Male factor is a common cause of infertility among couples trying to achieve a successful pregnancy. Half these patients have no identifiable cause for their infertility. Patients are classified as having unexplained male infertility (UMI) when there is no abnormality on history and physical examination, semen analysis, and hormone evaluation. The prevalence of UMI is approximately 15 % (range 6-37 %) in the general population. There are multiple immune, genetic, and environmental factors that may contribute to this condition. The objective of this chapter is to highlight the epidemiology and terms used to define unexplained male infertility.