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Fact sheet: Endometriosis

Last Update: October 17, 2011.

Endometriosis is still a fairly “unknown” illness, despite the fact that it is one of the most common gynecological problems. It often takes a long time before it is diagnosed. Some women who have endometriosis experience severe pain which affects their quality of life, and sometimes even their fertility. Extremely painful periods may be a sign of endometriosis. Good information and good doctors can help to get a clear diagnosis and determine what the best treatment options are. As with other chronic illnesses, it is important for women with endometriosis to find out how they can live as good a life as possible with their illness.

What is endometriosis?

During a woman’s reproductive years, between the ages of about 13 and 50, the mucous membrane lining her womb (endometrium) thickens once a month. In women with endometriosis, this endometrial tissue also grows in other parts of the body. These growths are benign (non-cancerous) and doctors call them “endometriotic tissue” or “implants”. Although they may grow bigger and sometimes affect other organs, it is extremely unlikely that they will develop into malignant (cancerous) tumors.

Like the endometrial tissue lining the womb, endometriotic tissue in other parts of the body also reacts to the female sex hormones and goes through cycles of growing and shedding. But because the cells and secretions that are released from endometriotic tissue during the monthly period cannot be expelled through the vagina, they stay in the woman’s body. This often goes unnoticed and does not have any consequences. Sometimes, however, scar tissue forms and grows together (adhesions), the tissue becomes inflamed or cysts develop. This can be very painful and make it difficult for a woman to get pregnant, especially if her ovaries or fallopian tubes are affected.

Endometriotic tissue and cysts usually grow in the pelvic and lower abdominal cavity (tummy area), for example on the outside wall of the womb, in the connective tissue of the womb and lower pelvic cavity, on the ovaries and in the pocket-like “pouch of Douglas” between the womb and the rectum (at the end of the bowel).

There are a number of theories about what causes endometriosis in some women, but scientists are not certain. One explanation is that there is something wrong with the interplay of their hormones or immune system. Our immune systems usually make sure that tissue which should grow in a certain part of the body cannot grow elsewhere. It is still unclear how endometrial tissue is able to grow outside of the womb.

cross-sectional view of abdomen

Figure: Endometriotic tissue in the abdomen

How common is endometriosis and how does it change over time?

Not all women who have endometriosis experience noticeable symptoms. Those who do not have symptoms often do not notice changes in the lower abdomen at all. For this reason it is difficult to estimate how many women actually have endometriosis. It is believed that about 40 to 60 out of 100 women (40% to 60%) who suffer from very painful periods have endometriosis.

Because period pains are so common, women generally only go to the doctor when their pain becomes worrying. On top of that, many doctors do not automatically think of endometriosis when a woman describes her symptoms. This means that it is typically only diagnosed many years after symptoms first arise. Women often first seek medical help if they are finding it difficult to get pregnant. You should therefore tell your doctor if you suspect that you have endometriosis.

It is very difficult to predict how a woman’s endometriosis will progress. It seems that it is unlikely to go away on its own without treatment, and the symptoms tend to get worse over time. Appropriate treatment can often limit further growth of endometriotic tissue and relieve the pain. The symptoms usually disappear when women stop having periods (menopause).

Endometriosis can either be mild (stages I and II) or moderate to severe (stages III and IV). Women who have moderate or severe endometriosis often have problems getting pregnant, particularly if their ovaries and fallopian tubes are affected. Mild endometriosis usually does not affect fertility.

What are the signs of endometriosis?

The most obvious symptoms of endometriosis are very strong pains and cramps in the lower abdomen. To start off with, these normally occur during the woman’s monthly period, but as the illness progresses they may be felt at other times of the month too. The pain sometimes radiates to the woman’s back and down her legs, and is often associated with nausea, vomiting and diarrhea.

The following symptoms may be signs of endometriosis:

  • Strong period pains (dysmenorrhea) that are so bad that low doses of painkillers do not help and the affected women are unable to perform their daily activities or go to work.
  • Pain during sexual intercourse (dyspareunia) or afterwards, which is normally described as burning or cramp-like.
  • Pain of varying intensity in different parts of the lower abdomen that also occurs between periods.
  • Feeling full, painful bowel movements, and bladder or bowel problems.

How are women’s lives affected by endometriosis?

More severe forms of endometriosis could affect nearly every area of a woman’s life. Many feel less womanly. Particularly young women with strong symptoms may not be able to develop a positive relationship to their own body. Painful sex can make it difficult to have an enjoyable sex life. Women who have more serious forms of endometriosis might not be able to become pregnant and have their own children. Chronic pain may lead to depression, tiredness and irritability. Together, all of these factors can place a heavy burden on a relationship.

For a considerable number of women, the recurring pain means that their everyday lives are repeatedly “disrupted” because they are unable to carry out their usual activities, go to work or pursue their hobbies. Women who cannot go to work due to their pains and cramps often face feelings of guilt and shame.

Having a supportive partner, family and friends is invaluable for many women. Some find it important to talk to other affected people in self-help groups, whereas others prefer to talk about their problems with people who are close to them.

You can read more about how women live with endometriosis and their experiences with the different treatment options in our interviews.

How is endometriosis diagnosed?

If endometriosis is suspected, you will first have an in-depth talk with your doctor or gynecologist about your symptoms (medical history) and he or she will give you a general check-up and pelvic exam. A pelvic exam involves feeling and looking at female organs using a speculum (plastic or metal instrument). These first steps will help to decide whether further tests are necessary. During a pelvic exam the doctor checks whether gently moving the womb and applying pressure to certain areas is painful. If lumps and hard areas in the pelvic connective tissue can be felt, this could also be an indication of endometriosis.

Larger areas of endometriotic tissue and bigger cysts can be detected by carrying out an ultrasound exam through the abdominal wall. In this way you can also see whether other organs like the kidneys are affected. Smaller areas and adhesions cannot be seen on ultrasound pictures. An ultrasound exam through the vagina is more appropriate for determining, for example, whether you have ovarian endometriosis.

It is sometimes possible to make a treatment decision at this point based on these examinations. Whether or not further tests are needed will depend on how bad the symptoms are.

To be able to determine with some certainty whether you have endometriosis, you may need to have surgery (a laparoscopy). This would involve making at least two small cuts (incisions). A tiny camera would be inserted into your abdomen through a small cut near your belly button. This would provide pictures of your abdominal and pelvic cavity, making it possible to find small areas of endometriotic tissue and adhesions. During this procedure doctors can also remove endometriotic tissue or take tissue samples (a biopsy) to find out whether it is endometriosis or another illness.

Like any other surgery, a laparoscopy carries some risks. It is performed under a general anesthetic and is only done if the woman’s symptoms are severe or if nearby organs are negatively affected. Laparoscopic surgery provides a clearer diagnosis before deciding what kind of treatment should be given.

The results of medical tests (medical or clinical findings) may not be directly related to the severity of a woman’s symptoms. The number or size of endometriotic tissue areas do not necessarily determine how much pain a woman feels. For example, one small area may cause more pain than several larger ones. In order to diagnose and treat endometriosis properly, it is important to find a doctor who also takes your symptoms into careful consideration.

What are the treatment options?

Because it is not clear what causes endometriosis and since there is no “cure” for it at the moment, the aim of treatment is to reduce the symptoms (symptomatic treatment). In terms of medication, painkillers and/or hormonal preparations are used. Many women also use complementary medicine. Surgery can be performed to remove the most of the endometriotic tissue and try to relieve or eliminate the pain.

Hormonal preparations suppress the production of hormones in the ovaries, usually suppressing the woman’s monthly period as well, with the aim of reducing the activity of endometriotic tissue. But the symptoms often return when women stop taking them. Hormone therapy can have adverse effects, so it is not always possible to have it for long periods of time. It is not suitable for women who would like to get pregnant.

In most cases endometriotic tissue can be removed using laparoscopic surgery. However, the tissue often grows back again within a few years after the operation and symptoms may return. Removing endometriotic tissue or adhesions through laparoscopic surgery could slightly increase the likelihood of natural conception in women who are having difficulties getting pregnant. Sometimes doctors suggest that women take additional hormones before or after having a laparoscopy. So far there is no scientific evidence that doing so helps. It has, however, been shown to have adverse effects.

Some women whose endometriosis affects their womb and causes unbearable pain decide to have their womb surgically removed in a final attempt to stop the pain. This operation is called a hysterectomy. Having a hysterectomy does not always fully cure endometriosis, especially if the ovaries are not removed at the same time. Doing so, however, would cause the production of female sex hormones to stop suddenly. This could lead to problems such as hot flashes like those commonly experienced during menopause.

The pains caused by endometriosis are also sometimes treated using complementary approaches. These include acupuncture, TENS (transcutaneous electrical nerve stimulation), applying heat and practicing techniques such as yoga or Tai Chi. So far, only little is known about the possible positive and negative effects of these approaches. What is more, they may have very different effects in different people. This is also true for changes in lifestyle, like more movement, stress reduction, relaxation techniques or eating different foods.

Finding a way to live as good a life as possible despite having endometriosis involves being well-informed and making a lot of decisions. To cope with the illness, it is important that you receive good medical care and support from doctors who have a lot of experience in the diagnosis and treatment of endometriosis. They should also be aware of the physical and mental burden of living with endometriosis. It can be helpful to ask for a second medical opinion when facing difficult decisions, such as whether or not to have surgery.

In Germany some clinics have specialized treatment programs for endometriosis, and some have opened “endometriosis centers”. These are a relatively new treatment form made up of different treatment modules. A number of different healthcare specialists work together in these centers, which are evaluated according to specific criteria ("certified"). They aim to make it possible for each woman to receive "holistic" treatment individually tailored to her own symptoms and circumstances, but there has not yet been any scientific research done on how effective this is. Follow-up treatment could have a benefit after surgery, or if symptoms do not go away despite extensive treatment.

You can find out more about the main diagnostic procedures here.


  • This information on endometriosis is based on an expert report that was prepared by the Institute for Quality and Efficiency in Health Care (IQWiG) for the German Federal Ministry of Health (BMG).
  • You can find the references for this fact sheet in gesundheitsinformation.de's article on endometriosis here.
© IQWiG (Institute for Quality and Efficiency in Health Care)

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