What it is

Endometriosis is a common health problem in women. It gets its name from the word endometrium, the tissue that lines the uterus (womb). In women with this problem, tissue that looks and acts like the lining of the uterus grows outside of the uterus in other areas. These areas can be called growths, tumors, implants, lesions, or nodules.

Most endometriosis is found:

    * on or under the ovaries
    * behind the uterus
    * on the tissues that hold the uterus in place
    * on the bowels or bladder

This "misplaced" tissue can cause pain, infertility, and very heavy periods.

Growths of endometriosis are almost always benign or not cancerous, but still can cause many problems. To see why, it helps to understand a woman's monthly cycle. Every month, hormones cause the lining of a woman's uterus to build up with tissue and blood vessels. If a woman does not get pregnant, the uterus sheds this tissue and blood, leaving her body through the vagina as her menstrual period.

Patches of endometriosis also respond to a woman's monthly cycle. Each month the growths add extra tissue and blood, but there is no place for the built-up tissue and blood to exit the body. For this reason, growths tend to get bigger and the symptoms of endometriosis often get worse over time.

Tissue and blood that is shed into the body can cause inflammation, scar tissue, and pain. As the misplaced tissue grows, it can cover or grow into the ovaries and block the fallopian tubes. This can make it hard for women with endometriosis to get pregnant. The growths can also cause problems in the intestines and bladder.