It is estimated that endometriosis affects between eight and 15 percent of women of reproductive age. Women with endometriosis have tissue similar to the tissue that lines the uterus (called the endometrium) growing in other areas of their bodies, for example, on the outside of the uterus or the ovaries. Although it is abnormal for endometrial tissue to grow outside of the uterus, endometriosis is not a form of cancer.

Endometriosis can occur at any time after puberty. It is most commonly diagnosed in a woman's twenties or early thirties; however, girls as young as eight have been diagnosed with the disease. A woman can also experience endometriosis after menopause, although this is relatively uncommon. It can also occur in women who have had a hysterectomy.

Some women with endometriosis have no symptoms whatsoever, some experience only mild symptoms, and others experience debilitating pain as well as other symptoms.

Endometriosis is treated in several ways. Treatment depends on factors such as the severity of a woman’s endometriosis, her age and whether or not she wants to get pregnant. Treatment may involve different combinations of medication, surgery, alternative approaches and/or lifestyle changes, depending on what you and your health-care professional decide on.