Endometriosis is a problem affecting a woman’s uterus – the place where a baby grows when she’s pregnant. Endometriosis is when the kind of tissue that normally lines the uterus grows somewhere else. It can grow on the ovaries, behind the uterus or on the bowels or bladder. Rarely, it grows in other parts of the body.
This “misplaced” tissue can cause pain, infertility, and very heavy periods.
Click here for more information http://www.nlm.nih.gov/medlineplus/endometriosis.html