What causes endometriosis?

Endometriosis is a difficult condition to understand, has a wide variety of symptoms, and as a result women often experience delays in their diagnosis.

We don't fully know what causes this disease, although risk factors that have a role in causing it include:

  • Family history: Women who have a close relative (mother, sister) with endometriosis are up to 7–10 times more likely to be diagnosed with it.
  • Retrograde (backwards) menstruation: During a woman’s period, the menstrual blood flows out of the vagina but also backwards along the fallopian tubes into the pelvic cavity (this is called retrograde menstruation). In most women, the menstrual blood, which contains endometrial cells, is absorbed or broken down by the body and causes no symptoms. However, in women with endometriosis, this endometrial tissue starts to grow in the wrong place.
  • Metaplasia: The conversion of the normal pelvic tissue into endometriosis.

Additional endometriosis risk factorsWoman holding stomach

  • Never given birth
  • Heavy or prolonged periods
  • Low body weight
  • Had their first period at an early age (before 11 years)
  • Frequent periods or short cycles (less than 27 days)
  • High estrogen levels—the hormone estrogen promotes endometriosis
  • Medical conditions that increase, block, or redirect your menstrual flow
  • A faulty immune system may fail to find and destroy endometrial tissue which grows outside the uterus.

Some of these risk factors can be changed through lifestyle, such as body weight. Others such as your family history cannot be changed.

While these risk factors can increase risk, they do not cause the disease. You may still have one or more of these risk factors and never develop endometriosis.

Symptoms of endometriosis include

  • Chronic and severe pelvic pain that affects normal activities
  • Pain just before or during your periods (dysmenorrhea)
  • Ovulation pain; pain with intercourse
  • Heavy, irregular or long periods
  • Pain with bowel movements or urination
  • Infertility.

Serious pain during a period is not normal—Any period pain that affects your ability to go about your daily activities should be investigated.

It is possible that some women with this disease may not have symptoms. Endometriosis pain levels are not associated with the amount and extent of the disease. For example, women may have severe pain with mild endometriosis, or advanced endometriosis with minimal or no pain. Symptoms can vary from person to person depending on where the endometriosis is in the body.

This condition can grow on the ovaries, fallopian tubes and the inner lining of the pelvis, less commonly it may also spread to other organs beyond the pelvic area.

Endometriosis and infertility

Women with this disease are at higher risk of experiencing infertility, however they may still be able to conceive and become pregnant naturally.

Severe endometriosis can influence fertility by distorting the fallopian tubes and ovaries—it can block the egg’s release by causing adhesions or scar tissue. Inflammation can also impair the function of eggs and sperm creating difficulty with fertilisation, embryo development and implantation.

Evidence also suggests that the quality and quantity of eggs in women with endometriosis is affected, although it's uncertain whether this is a direct effect of the endometriosis.


While there is no cure for this condition, early detection and treatment can help manage it and target symptoms.

It’s a common myth that this condition can be cured by a hysterectomy. Endometriosis is a disease outside of the uterus, and removing the uterus alone will not cure endometriosis. 

In some cases, a hysterectomy can be an appropriate recommendation to a patient when pain is the major factor affecting her quality of life, she has completed her family, all other conservative treatments have not stopped the pain, and who might have accompanying conditions like adenomyosis, which affects the muscle layer of the uterus. There are many steps in modern treatments to take before this option, and there is no guarantee it will stop the symptoms fully.

More information about the diagnosis, types, and treatment plans can be found on the Endometriosis page.

I specialise in managing complex and severe endometriosis cases in collaboration with general gynaecologists, bowel and urological surgeons. If you would like to make an appointment, please contact me.

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