A not uncommon history looks like this: A young, slim and fully active woman had always had mild complaints before and during her periods. When she then took the pill, these got better.
But when she toyed with the idea of pregnancy and stopped taking the pill, the complaints came back. Only the desired pregnancy failed to materialize.
Endometriosis is caused by tissue of the uterine lining that is in the wrong place. Usually in the abdominal cavity, i.e. on the peritoneum, the ovaries or behind the uterus in the so-called Douglas' space, the lowest point of the abdominal cavity. In principle, such tissue islands can occur anywhere in the body.
According to the female cycle, this mucous membrane builds up and degrades under the natural influence of hormones. In the uterus, the blood that forms can drain away. In the abdominal cavity, however, the blood that forms leads to complications: Cysts can form, the blood leads to an inflammatory stimulus ("sterile inflammation") or tissue adhesions and adhesions develop, e.g. between the intestinal loops.
One of the most important complications is sterility, i.e. the inability to become pregnant. In women with an unwanted pregnancy, endometriosis is found about twice as often as in women with children.
In abdominal surgeries, single endometriosis foci are found in about 6-8% of all cases. However, by no means all of these women have symptoms!
Apparently, tissue from the uterus settles relatively often in other parts of the body. Thus, some inward bleeding is apparently largely normal.
However, the body recognizes these cells and removes them. In some cases, however, this apparently does not happen. The cause of this is unknown. Disturbances of the immune system are discussed.
It is not known why some women have severe symptoms and others - despite more intensive infestation - do not complain of pain. Certainly, the location of the infestation also determines the complaints. However, these also depend on the individual pain threshold. The lower this is - e.g. with fibromyalgia - the more complaints are present.
Studies (Hum Reprod. 2002 Oct;17(10):2715-24) showed that patients with endometriosis suffered more of the following:
- CFS - chronic fatigue syndrome
- Allergic diseases
- Rheumatic diseases (such as Sjögren's syndrome or rheumatoid arthritis)