What causes endometriosis?
It is not known what causes endometriosis, but it may be genetic and may be related to hormones. There are treatments for endometriosis, but there is no cure for the condition.
Why does endometriosis cause pain?
When you have your period and the endometrium bleeds in the uterus, it will also bleed in the other locations where the abnormal tissue grows. It leads to inflammation, blood accumulation, scar tissue and pain.
The mucosa-like tissue that makes up endometriosis is affected by hormones in the same way as the normal tissue in the uterine cavity. When you are affected by hormones in your cycle, your endometriosis will also be affected. In the uterus, the blood will be pushed out when bleeding from the vagina, but in the case of endometriosis, which is located elsewhere where the blood does not have the opportunity to find a way out, small blood cysts will form.
How and how much pain is common?
Women with endometriosis often experience severe pain during menstruation and have a poor effect on painkillers. Some also experience pain during ovulation and in the days before menstruation. The pain outside the uterus is localized where the endometriosis grows – be it in the bowel during defecation, shock pain during intercourse or pain during urination. If the endometriosis has been allowed to develop over many years, the pain can become constant. This also applies if the endometriosis presses on nerves and painful areas. Walking with pain over time can lead to reduced sleep quality, altered appetite and fatigue.
Why can it be difficult to make the diagnosis?
The symptoms of endometriosis can easily be confused with conditions from the organs that are affected. For example, endometriosis in the bladder can be confused with a urinary tract infection. In the gut, it can be interpreted as part of irritable bowel. Often the symptoms can worsen over time when you have had many periods that have affected the tissue time and time again. This will make the diagnosis clearer as the years go by and it is easier to link it to e.g. cyclical pain.
Estrogen is a prerequisite for the development of endometriosis. The symptoms appear in childbearing age and will for most people decrease with menopause. Birth control pills can be used as part of the investigation, if the pain subsides when using the pills, it could provide a good clue.
What is the difference between endometriosis and adenomyosis?
Endometriosis is a condition where tissue similar to the lining of the womb (the endometrium) grows outside the womb. This tissue can be found on the ovaries, fallopian tubes, peritoneum or other organs near the uterus. Adenomyosis, on the other hand, is a condition where the endometrium grows inside the muscle tissue of the uterus (the myometrium). This leads to thickening of the uterus and can cause increased bleeding during the menstrual cycle. Adenomyosis can also lead to painful periods, chronic pelvic pain and in some cases infertility. The exact cause of adenomyosis is unknown, but hormonal and genetic factors may play a role. You can read more about adenomyosis here.

