Endometriosis is a common health problem in women. It is a common cause of severe recurring pain in women. One in every 5 women belonging to 13 to 45 age group suffer from endometriosis. Yet, it is not uncommon in women after menopause.

The primary problem lies with the 'endometrium', which is the normal inner lining of the uterus. The uterus houses the baby when the woman is pregnant. In endometriosis, these cells of inner lining of the uterus grow in places other than the uterus. Most commonly, these cells are found growing in locations like the ovaries, fallopian tubes, or anywhere within the pelvic cavity. In rare cases, these tissues are found in the lungs, skin, eye, diaphragm and the brain.

In normal conditions, the endometrium within the uterus is shed periodically during the bleeding that occurs in the menstrual cycle. But, in endometriosis, the endometrium being situated elsewhere in the body is unable to exit the body. Nevertheless, it proliferates and cyclically, the bleeding also occurs, but into the body cavity wherein it is situated!! The endometrium detaches itself, and remains shed within the cavity. The shed materials consist of degraded blood and tissues, which are sufficient to cause irritation and often severe pain in the affected area. Endometriosis depending upon its location can even affect the normal functions of organs like bladder, bowels and the intestines.

Repetitive irritation and pain can cause internal changes in the normal structures of the affected body part due to adhesions and scar formations. In very advanced cases, the internal organs of the pelvis fuse together in a condition called 'frozen pelvis'. Endometriosis is a leading cause for infertility in women.

The most common presentation is pelvic pain. Largely, the pains are timed with the occurrence of the menstrual cycle though it can certainly occur at other times. These pains vary in nature, though commonly they are severe, crampy and spasmodic. These can cause nausea and vomiting also.

Many theories have been put forth to explain the cause of endometriosis, though none till date have clearly explained it! So, the real cause of endometriosis remains unknown.