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Endometriosis

A benign condition in which tissue that looks like endometrial tissue grows in abnormal places in the abdomen.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

About Endometriosis

Endometriosis is one of the most common medical conditions affecting the lower abdomen (lower belly) in women. In endometriosis, the kind of tissue that normally lines the inside of the womb (endometrial tissue) also grows outside of it. This can happen without the woman being aware of it. But in other women endometriosis is a chronic disease, associated with severe pain and fertility problems.

It often takes years for endometriosis to be diagnosed as the cause of these problems. Until the diagnosis is made, many women try to cope with their pain somehow. They believe that the pain — even really bad pain — is a normal part of their menstrual period.

There is currently no cure for endometriosis. But there are many things that can be done to relieve the symptoms. And if treatment is adapted to suit women's personal circumstances and the severity of their endometriosis, many can cope quite well with the disease.

Like with other chronic conditions, it is important to get to know your own body and how it reacts, in order to find ways to manage the symptoms. Getting hold of good information and consulting experienced, supportive doctors can help... Read more about Endometriosis

What works? Research summarized

Evidence reviews

Endometriosis: Diagnosis and Management

This guideline makes recommendations for the diagnosis and management of endometriosis in community services, gynaecology services and specialist endometriosis services (endometriosis centres).

There is no evidence that hormonal suppression either before or after surgery for endometriosis is associated with a benefit

Endometriosis is caused by the lining of the uterus (endometrium) spreading outside the uterus. It can cause pelvic pain, painful periods and infertility. Common treatments are hormonal suppression with medical therapy to reduce the size of endometrial implants or laparoscopic surgery (where small incisions are made in the abdomen) to remove visible areas of endometriosis. There is no evidence that hormonal suppression either before or after surgery is associated with a benefit compared with surgery alone.

Hormone therapy for women with endometriosis and surgical menopause

Endometriosis is known to result in variable severity of symptoms. For some women bilateral removal of the ovaries (oophorectomy) with or without an hysterectomy may be required to manage symptoms. This brings women into premature menopause. It is thought that hormone replacement therapy may enhance the recurrence of the disease due to its effect on the remaining endometriotic deposits in the pelvis. Only two small randomised controlled were identified in the literature that looked at this problem. Further research is required to clarify the effect of different hormone replacement therapy types on the recurrence of the disease and the associated pain including during sex.

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Summaries for consumers

What causes endometriosis?

In endometriosis, the kind of tissue that lines the womb (endometrial tissue) also grows outside the womb. It is still not clear why this happens. There are various theories about what causes endometriosis. Several factors probably play a role.The inside walls of the womb (uterus) are completely lined with mucous membranes known as the endometrium. These are different to other mucous membranes in the body, particularly in their ability to change: Every month, new endometrial cells grow and the tissue thickens in case a fertilized egg settles in it. The thickened tissue can then provide the egg with everything it needs to grow. If fertilization doesn't take place and the woman doesn't become pregnant, most of the thick membrane tissue which has built up is shed and leaves her body during her period. The process of building up and shedding the lining of the womb is regulated by the female sex hormones estrogen and progesterone.Illustration: Womb without endometriosis - as described in the articleEffect of hormones on the lining of the womb (uterus) during a menstrual cycle Illustration: Effect of hormones on the lining of the womb (uterus) during a menstrual cycleIn endometriosis, the kind of tissue that normally lines the womb also grows in other parts of the body. Medically speaking, there are different types of endometriosis, depending on where the endometrial tissue grows.In the muscles of the womb or in the wall of a fallopian tube, where the tissue is attached to the lining of the womb (common);In the lesser pelvis, including the ovaries, fallopian tubes and the “Pouch of Douglas” found between the womb and rectum at the end of the bowel (common);Outside this area of the pelvis, for instance in the bladder or bowel (rare), and very rarely in parts of the body that are further away, like the lungs.Every month during the menstrual cycle, the mucous membrane tissue in endometrial implants outside of the womb is also built up and shed. But because the blood and shed tissue can't leave the woman’s body through her vagina, they stay near the endometrial implant. Here they can lead to inflammations, which in turn can cause scarring and adhesions (when tissue sticks together).Illustration: Endometrial implants in the abdomen – as described in the article

Endometriosis: Surgery: What are the advantages and disadvantages of having hormone therapy too?

There is no proof that taking hormone medication before or after endometriosis surgery improves the outcome of the treatment. But hormone products such as GnRH analogues often have side effects and reduce fertility during treatment.

There is no evidence that hormonal suppression either before or after surgery for endometriosis is associated with a benefit

Endometriosis is caused by the lining of the uterus (endometrium) spreading outside the uterus. It can cause pelvic pain, painful periods and infertility. Common treatments are hormonal suppression with medical therapy to reduce the size of endometrial implants or laparoscopic surgery (where small incisions are made in the abdomen) to remove visible areas of endometriosis. There is no evidence that hormonal suppression either before or after surgery is associated with a benefit compared with surgery alone.

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Terms to know

Endometriotic Tissue (Endometriotic Lesion)
Tissue that normally grows inside the uterus, grows outside the uterus.
Endometrium
The layer of tissue that lines the uterus.
Estrogen
A type of hormone made by the body that helps develop and maintain female sex characteristics and the growth of long bones. Estrogens can also be made in the laboratory. They may be used as a type of birth control and to treat symptoms of menopause, menstrual disorders, osteoporosis, and other conditions.
Fallopian Tubes
A slender tube through which eggs pass from an ovary to the uterus. In the female reproductive tract, there is one ovary and one fallopian tube on each side of the uterus.
Hormones
A messenger molecule that helps coordinate the actions of various tissues; made in one part of the body and transported, via the bloodstream, to tissues and organs elsewhere in the body.
Ovarian Cysts
An ovarian cyst is any collection of fluid, surrounded by a very thin wall, within an ovary. Any ovarian follicle that is larger than about two centimeters is termed an ovarian cyst. The vast majority of ovarian cysts are harmless (benign). Some ovarian cysts cause problems, such as bleeding and pain.
Pouch of Douglas
A sac or recess formed by a fold of the peritoneum.
Progesterone
A type of hormone made by the body that plays a role in the menstrual cycle and pregnancy. Progesterone can also be made in the laboratory. It may be used as a type of birth control and to treat menstrual disorders, infertility, symptoms of menopause, and other conditions.
Tissue
A group of cells that act together to carry out a specific function in the body. Examples include muscle tissue, nervous system tissue (including the brain, spinal cord, and nerves), and connective tissue (including ligaments, tendons, bones, and fat). Organs are made up of tissues.
Uterus (Womb)
The small, hollow, pear-shaped organ in a woman's pelvis. This is the organ in which a fetus develops. Also called womb.

More about Endometriosis

Photo of a young adult woman

Also called: Endo

See Also: Dysmenorrhea, Menstruation

Other terms to know: See all 10
Endometriotic Tissue (Endometriotic Lesion), Endometrium, Estrogen

Related articles:
Causes of Endometriosis
Information for Partners of Women with Endometriosis

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