Unexplained infertility: does it really exist? Does it matter?

Unexplained infertility (UI) refers to a diagnosis made in couples in whom standard investigations including semen analysis, tests of ovulation and tubal patency are normal. It has been suggested that the term UI is unsustainable, as conditions such as endometriosis, tubal infertility, premature ovarian ageing and immunological infertility tend to be misdiagnosed as UI. In this debate, we present the view that, although scientifically unsatisfying, the diagnosis of UI is sustainable from a clinical and practical perspective. Given our present treatment options, further investigations leading to a more 'accurate' diagnosis is unlikely to change our management in these cases. Scientific curiosity must take second place to a more pragmatic approach, which takes into account the clinical and financial costs of making a more 'accurate' diagnosis.