The classification of endometriosis. A literature overview and a proposal for a new classification system for endometriosis and infertility

Endometriosis is responsible for major morbidity in women of childbearing age. Although there is reasonable evidence confirming an association between endometriosis and infertility, a causal relationship has not yet been established. Endometriosis is also responsible for impairment of quality of life, which may be present from menarche to the fourth decade, and sometimes even in menopausal years. Although we do not yet fully understand the underlying pathophysiology, more and more evidence is arising as this being multifactorial in origin with possible genetic susceptibility. Patients need effective, safe treatment and if possible cure of their disease state, with restoration of fertility if impaired and delivery from the everyday clinical symptoms associated with active disease. Clinicians need accurate screening tools for disease, with high specificity, diagnostic tests to confirm suspected disease, and ultimately treatment modalities to offer their patients. Severity of disease usually correlates with degree of impairment of function. Severity or stage is usually based on degree of organ involvement, whether being functional or anatomical. A staging system should be based on the natural history of the disease, its local invasiveness, and its functional as well as organic consequences.