Endometriosis is a chronic, benign disease in women in which the mucous membrane tissue that normally covers the inside of the uterus also occurs outside the uterus. Women with endometriosis can suffer from menstrual pain, but also with pain and or blood loss during sex and pain when urinating and bowel movements. Fatigue can also occur. If the disease is not treated in a timely manner, it can lead to infertility.

It is estimated that more than one in ten women between the age of 15 and 50 would suffer from endometriosis to a greater or lesser extent. Early detection and diagnosis is of great importance for proper treatment and preservation of fertility. The fact is that the diagnosis sometimes takes a long time.

Symptoms can occur in adolescents who are often told that they simply have painful periods or that the pain is due to stress. Quite a few women are often afraid that to be seen as faint and weak and no longer talk about the pain, which diagnosis difficult.

What is endometriosis?

The inside of the uterus is lined with mucous membrane tissue (endometrial). Normally, this mucous membrane is only in the uterus, but with endometriosis there are also pieces of mucous membrane outside the uterus. For example, in the abdominal cavity, on or in the ovaries, between the uterus and the bladder or rectum, in the intestinal wall or in the bladder, deep in the wall of the uterus itself (which is called adenomyosis), or, very occasionally, outside the abdominal cavity in other organs.

Under the influence of hormones, that uterine mucosa thickens a little every month to allow a pregnancy. If there is no fertilization, the built-up mucous membrane is broken down and repelled again. That’s menstruation.

Also, the pieces of mucous membrane that are located outside the uterus (the endometriosis fireplaces) grow and break down every month. This causes small bleeding in the abdominal cavity, ovaries, etc. that cannot be removed through menstruation. This leads to irritation of the peritoneum or of the organs where they are located.

Small scars and growths and so-called adhesions between organs can also occur and over time sometimes chronic inflammation of the endometriosis fireplaces.

In the ovaries, cavities (cysts) filled with old blood can also form. Such cysts are called endometriomas or ‘chocolate cysts’ because of their dark brown color. They would occur in about 10% of women with endometriosis.

There are several forms of endometriosis:

  • Superficial endometriosis: isolated flat areas on the peritoneum.
  • Extensive endometriosis: nodules (noduli) that can grow in surrounding organs such as bladder, urinary tract, intestine and vagina wall.
  • Endometriosis cysts (endometriomas): cysts in the ovary(s).

How does endometriosis occur?

How endometriosis develops and why some women do and others don’t get it isn’t entirely clear. It is probably a combination of several factors.

  • Hormones

The female hormone estrogen plays a crucial role. This explains why endometriosis occurs only in women of childbearing age (from about 15 to 50 years), and why the symptoms usually disappear after menopause. It also explains why the risk of endometriosis is higher in women who menstruate from an early age and who enter ‘menopause’ late and in women who have not (yet) or not often been pregnant. It also explains why the symptoms usually decrease with a hormonal treatment that reduces estrogen production, such as the pill.

  • Retrograde menstruation

With each menstruation, a small amount of blood and repelled uterine mucosa can enter the abdominal cavity through the fallopian tubes. When this mucous membrane implants in the abdominal cavity and begins to grow, endometriosis could develop. But that retrograde menstruation, which occurs in about 90% of all women, is not enough to cause endometriosis.

  • Cell mutation

According to another theory, endometriosis is caused by a change or mutation of endometrial cells, which can therefore also develop outside the uterus. Or arguably cells outside the uterus that at some point in their development, for some reason, do not perform their normal function but grow into endometrial cells.

  • Heredity

The fact is that women who have a mother or sister with endometriosis have a greater risk of developing endometriosis themselves. In addition, daughters of a mother with endometriosis often have a more severe form of endometriosis.

  • Immunity disorder

Women with endometriosis may have an immune disorder that prevents the mucous membrane located outside the uterus from breaking down and developing abnormally.

Low body mass index, heavy menstruation, menstruation at a very young age and a short menstrual cycle are also possible risk factors.

  • Environmental factors

According to some studies, certain substances in the environment (such as dioxins, PCBs) would interfere with the action of hormones and of the immune system and thus contribute to the development of endometriosis, but there is no scientific consensus on this yet.

  • Nutrition

The consumption of red meat and trans fatty acids could encourage the occurrence of endometriosis. Obesity would also be a risk factor.

No risk factors

Some factors are sometimes mistakenly considered responsible for the onset of endometriosis: vaginal showers, STDs such as chlamydia and gonorrhea, a pregnancy interruption. There is no evidence that these elements would contribute to the development of endometriosis.

Who can get endometriosis?

Endometriosis occurs only in women who menstruate. It occurs between the earliest from the first periods and usually stops after the last menstruation.

Endometriosis usually only appears after a few years of menstruation, so especially for from the age of about 20-25 years, with a peak between 35 and 45 years. But the disease can also occur in young girls who are newly menstruating.

For example, a recent research showed that one in twenty young girls in high school have very painful periods that do not stop with classic painkillers. Possibly about 60 to 70% of those young girls would have endometriosis.

Therefore, it is recommended that girls consult their doctor during very painful periods and be followed up further. This certainly applies to menstrual pain that does not respond to regular painkillers or when the pain seriously disrupts normal functioning (at school, leisure, etc…) The starting point should be that menstrual pain in young girls is not normal and needs to be further investigated.

When to see the doctor?

If you often have abdominal pain or other symptoms during your periods that may indicate endometriosis, it is best to consult your doctor. Painful periods are not normal. Especially when the pain does not go away when you take a painkiller or if you are also in pain when you take the pill.

Diagnosis: How is endometriosis diagnosed ?

A gynaecological examination is carried out to check whether your symptoms are caused by endometriosis. Ultrasound and blood tests sometimes provide additional information. Keyhole surgery (laparoscopy) with tissue examination can make it clear whether endometriosis is indeed involved.

  • Gynaecological examination

As a first step in diagnostics, the doctor will inquire about the complaints and do an internal examination. This allows him/her to detect any cysts on the ovaries, small, sometimes painful-feeling nodules on the uterine wall, and endometrial spots in the vagina wall.

  • Ultrasound

With a vaginal ultrasound, the various organs of the small pelvis are visualized on a screen. As a result, an enlargement of or a cyst can be seen on the ovaries. Mild forms of endometriosis are not seen in ultrasound examination.

  • Laparoscopy

To be sure of diagnosis, keyhole surgery (laparoscopy) should be performed. A viewing instrument is inserted via a tiny cut at the level of the navel, along which the organs of the small pelvis can be viewed directly. In addition, a small piece of tissue is usually removed (biopsy) to examine it.

  • Other tests

Sometimes blood tests are prescribed to determine the value of the CA125. The branded substance CA125 may be elevated with more extensive forms of endometriosis, but is often normal with lighter forms.

Sometimes additional examination is recommended, such as a CT scan or an MRI or a radiography of the large intestine or urinary tract. As is the case with an ultrasound examination, light forms of endometriosis are not noticed with these tests.

Getting pregnant with endometriosis

Women with severe endometriosis often find it difficult to conceive spontaneously, even after surgical treatment. In that situation, you may consider intrauterine insemination (IUI) or in vitro fertilization (IVF). In IUI, the gynecologist brings the sperm directly into the uterus. In IVF, the sperm fertilize the eggs in a test tube. The fertilized egg is then placed back in the uterus.

Elena Mars

Elena writes part-time for the Scientific Origin, focusing mostly on health-related issues.