What is endometriosis?
Endometriosis is a disorder in which bits of tissue from the inner lining of the uterus (the endometrium) grow inside a woman's body, outside of the uterus. The uterus is a hollow organ within a woman's abdomen where a fertilized egg implants and where a developing baby is nourished and grows.
Endometriosis is a growth of cells similar to those that form the inside of the uterus (endometrial cells) outside of the uterus. Endometrial cells are the same cells that are shed each month during menstruation. When endometrial cells grow outside the uterus, endometriosis results. These cells attach themselves to tissue outside the uterus and are called endometriosis implants. The implants are most commonly found on the ovaries, the fallopian tubes, outer surfaces of the uterus or intestines, and on the surface lining of the pelvic cavity. They can also be found on the liver, vagina, old surgery scars, and even in the lung or brain. Endometrial implants are generally benign (not cancerous).
Endometriosis is a painful, chronic disease that affects 5 1/2 million women and girls in the USA and Canada, and millions more worldwide. It occurs when tissue like that which lines the uterus (tissue called the endometrium) is found outside the uterus -- usually in the abdomen on the ovaries, fallopian tubes, and ligaments that support the uterus; the area between the vagina and rectum; the outer surface of the uterus; and the lining of the pelvic cavity. Other sites for these endometrial growths may include the bladder, bowel, vagina, cervix, vulva, and in abdominal surgical scars. Less commonly they are found in the lung, arm, thigh, and other locations.
This misplaced tissue develops into growths or lesions which respond to the menstrual cycle in the same way that the tissue of the uterine lining does: each month the tissue builds up, breaks down, and sheds. Menstrual blood flows from the uterus and out of the body through the vagina, but the blood and tissue shed from endometrial growths has no way of leaving the body. This results in internal bleeding, breakdown of the blood and tissue from the lesions, and inflammation -- and can cause pain, infertility, scar tissue formation, adhesions, and bowel problems.
When a woman has endometriosis, the tissue that lines her uterus, called the endometrium, grows outside of the uterus. No one is sure why this happens. When this tissue grows outside of the uterus, it is mostly found in the pelvic cavity, usually in one or more of these places: on or under the ovaries, behind the uterus, on the tissues that hold the uterus in place, or on the bowels or bladder. In very rare cases, endometriosis areas can grow in the lungs or other parts of the body.
As the tissue grows, it can develop into growths, also called tumors or implants. These growths are usually benign (not cancerous) and rarely are associated with cancer. Growths can cause mild to severe pain, infertility (not being able to get pregnant), and heavy periods.
The endometriosis growths are affected by the monthly menstrual cycle. Each month, the lining of the uterus thickens to get ready for pregnancy. If a woman does not become pregnant, the lining of the uterus sheds and the woman bleeds. When a woman has endometriosis, the growths outside of the uterus also bleed during her period. But there is no way for the blood to leave her body, and inflammation and scar tissue can develop. Blockage or bleeding in the intestines and problems with bladder function may also occur.