Dislodged tissue of the uterine lining – an estimated one in ten women in Germany suffers from it. Nevertheless, it sometimes takes years until the correct diagnosis is made. Endometriosis is derived from endometrium, the term for the lining of the uterus. Normally, this mucous membrane lines the inside of the uterus. However, it can also settle in other places, such as the fallopian tubes or ovary, in the abdomen, and even deep in the muscles of the uterus. Other locations in the body are possible, but rare. Endometriosis is one of the most common diseases in women of sexually mature age. It is the underlying cause in about one in three women who remain unintentionally childless.
Uterine lining: Building up and breaking down in constant alternation
During childhood, the endometrium is a dormant tissue. Only with the onset of puberty and increasing levels of estrogen in the blood does it begin to grow in order to prepare the uterus for the implantation of a child, until finally the first menstrual bleeding occurs, during which the excess mucosa is shed. From then on, the endometrium is subject to constant change.
The female cycle
Under the influence of estrogens, the endometrium is built up during each menstrual cycle. It continues to grow through an interplay of estrogens and progestins until it finally matures at the time of ovulation. It is now ready to receive an egg. If the egg is now fertilized, it can implant in the lining of the uterus and the development of a new life begins.
If fertilization fails to occur, the body no longer needs this mucosal layer. The hormones fall off, the layer disintegrates and is shed. This causes bleeding, after which the build-up of the mucous membrane begins again. Only with the onset of menopause and the drop in estrogen levels does this cycle finally stop.
Irritation and inflammation
The scattered endometrial foci also react to the hormones in the blood like the normal endometrium, so they change during each menstrual cycle. However, the blood then formed to reject the tissue cannot leave the body through the vagina as normal.
Instead, it flows into the abdominal cavity, for example. From there, it is slowly reabsorbed by the body, but the recurrent tissue breakdown outside the uterus causes irritation and inflammation.
Chocolate cysts
In the long term, this leads to adhesions and changes in the affected areas. If blood accumulates in an organ, this leads to so-called chocolate cysts on the ovaries, for example. These are cavities filled with clotted old blood that appear brownish – hence the name.
How do endometriosis lesions develop?
To date, there are only theories about how endometriosis develops. For example, it is discussed that the disease is the result of uncontrolled growth, whereby the mucous membrane grows into the depth of the uterine muscles or spreads to other organs. And it is thought that endometrial tissue can be carried into the abdomen by a reflux of menstrual blood and then colonize there.
Endometriosis: hereditary component
Another hypothesis is that cells that originated from the same original tissue in the womb can transform into endometrium, leading to endometriosis. The disease also occurs in clusters in some families, so that a hereditary component must be assumed. However, none of the current theories can adequately explain all the phenomena of endometriosis.
