Epidemiology of endometriosis.

Endometriosis is a cause of acquired dys- menorrhoea, dyspareunia, intermenstrual bleeding and menorrhagia, infertility, and pelvic pain of varying severity and location.'The disease is seen as one with obscure determinants, with little known about its distribution in the population, and with poor response to treatment.This review evaluates the current knowledge on the epidem- iology of endometriosis. Disease descriptionEndometriosis was recognised as a pathological entity only in the 1860s, and as a recognisable clinical problem in the 1920s.2It is a condition in which tissue with the histological structure and physiological responses of uterine mucosa occurs in sites other than the uterus; commonly within the pelvis.2The implants produce vesicles or haemor- rhages that are seen as blue, brown, or black nodules on peritoneal surfaces of the pelvis.If severe, the implants may go on to produce fibrosis and adhesions.3It is not known why implants that do not cause physical distortion are associated with infertility or cause disproportionate pelvis dis- comfort.4Little is known about the natural history of endometriosis.' 7 Because the physical findings are non-specific, clinical findings can be confused with those of pelvic inflammatory disease, benign or malignant ovarian disease, fibroids, and gastro- intestinal or urinary problems.Since the 1970s, diagnostic confirmation has been possible by directly visualising the pelvis using a laparoscope.Before this, laparotomy was the only confirmatory method possible.