What Is Endometriosis?


The womb, or uterus, is a part of the female reproductive system. It has three tissue layers, namely the perimetrium, the myometrium, and the endometrium the innermost lining of the uterus. When tissues of the endometrium are present in places other than in the endometrial layer of the uterus, that condition is called endometriosis. The word “endometriosis is derived from the Greek endo ‘'inside'', metra ''uterus'' and osis ‘' disease”.1,2 

Endometriosis is a chronic disease and affects women of any age within their reproductive age which is roughly up to 10% of women in their reproductive age in the UK. It remains, to some extent, an unclear disease, with an average diagnosing time of 7.5 years and clinical symptoms ranging from pelvic pain to infertility.1

Causes of endometriosis

The exact cause of endometriosis is still unclear. However, there are a few theories and hypotheses to explain the origin of endometriosis. These are the theories that researchers and doctors believe are the origin of endometriosis:

  • Retrograde menstruation: During normal menstruation, endometrial tissues shed from the inner uterine lining are expelled through the cervix and vagina. But in this scenario of retrograde menstruation, menstrual blood containing endometrial tissues flows back into the fallopian tubes in a reverse direction and is expelled into the pelvic cavity. This results in the deposit of endometrial cells in places outside the uterus within the pelvic cavity4
  • Transformation/Cellular metaplasia: Cells at other places of the body are automatically transformed into endometrial cells and start growing
  • Transportation via blood and lymph: Endometrial tissues are carried into other places of the body via blood and lymph in a similar way to the spread of cancer cells inside the body
  • Direct transplantation: In surgery, during procedures (e.g. Caesarean section) where endometrium is exposed, cells from the endometrial lining may get attached to other body areas like the pelvic wall and outer uterine wall
  • Genetics: Some families seem to be affected more by endometriosis.

Signs and symptoms of endometriosis

The symptoms of endometriosis may vary. Some women are severely affected, while others might go without having any symptoms. Having more symptoms or more pain does not indicate severe endometriosis.

The most  common symptom of endometriosis is pain in the pelvis. This pain may be most noticeable during: 

  • Menstruation This is a commont symptoms of endometriosis. This may include abdominal cramps and cramping pain in the lower back
  • During or after sex
  • While passing urine
  • While defecating

 Apart from pain, there are other symptoms that are common in endometriosis.

  • Constipation or diarrhoea during your period
  • Low energy, fatigue and muscle and joint pains during a period
  • Irregular periods in varying intervals
  • Heavy menstrual bleeding
  • Spotting or bleeding patches in between periods

Infertility or fertility problems are another huge concern associated with endometriosis.  Endometriosis is one of the most common causes associated with female infertility. Even though there is no clear mechanism explaining how endometriosis is causing infertility research shows that 25% to 50% of women who are infertile have been diagnosed with endometriosis and 30% to 40% of women who are diagnosed with endometriosis are infertile.2

Fertility problems can be caused by:.

  • Adhesions: "sticky" areas of endometriosis tissue that can join organs together
  • Scarring: Scarring of ovaries can affect the release of eggs after ovulation. After r eggs are released by the ovaries they need to be carried into the uterus via fallopian tubes to conceive. Scarring of fallopian tubes may also disturb eggs from reaching the uterus
  • Fluid: The tissue lining which covers the abdominal wall inside is called the peritoneum Endometriosis can affect the functions of your peritoneum. With endometriosis the amount of fluid collected inside the peritoneum increases. This fluid contains substances that can affect the functions of your eggs, fallopian tubes and sperm
  • Chemical and structural changes:chemical and structural changes affecting the lining of the uterus can affectembryo implantation inside the uterus. Even if implantation is succesful,  it may release which results in miscarriages3

Management and treatment for endometriosis


A doctor or GP may suspect endometriosis based on symptoms and physical examination. If they suspect endometriosis, they will offer further investigations with a gynaecologist to confirm the diagnosis. 

  • Laparoscopy: This is a procedure where a doctor will make a small cut in the abdomen and a camera with a light will be insertedto visualise the inside of the abdominal cavity. This will allow a doctor to clearly see outside the uterus, ovaries, fallopian tubes and surrounding structures and any lesions corresponding to endometriosis in the abdominal cavity. This investigation remains the gold standard investigation to diagnose endometriosis
  • Biopsy: If adoctor finds any suspicious tissues during a laparoscopy, they will scrape off a few samples from the area and send them to a laboratory. Then a pathologist will confirm the diagnosis of endometriosis

A doctor may use the terms “nodules”, “implants” or “lesions” to describe affected areas of endometriosis. Affected areas may include:

  • The ovaries where eggs are produced and stored
  • The fallopian tubes, the long tube-like structures lying beside the uterus that carries egg cells to the uterus from the ovaries
  • The outside surface of the uterus
  • Uterine ligaments: the tissues responsible for supporting and anchoring the uterus in position
  • The space between the uterus and the rectum or bladder 

However, rarely these tissues can be present outside common organs in places like:

  • The cervix
  • The bladder
  • The vagina or vulva
  • The lungs
  • The intestines
  • The rectum
  • The stomach (abdomen)


Currently, there is no cure or definitive treatment for endometriosis. However, a doctor can prescribe treatments so that endometriosis may not interfere with daily life. Some  treatment options include5,

Gynaecologist will prescribe and discuss treatment options and outline the benefits and risks of each. Several factors affect when determining a suitable treatment option. Factors include:

  • Age
  • Main symptoms like pain or infertility
  • Location for surgery
  • Previous treatments

Sometimes treatments are nor prescribed if:

  • Symptoms are mild
  • There are no fertility problems
  • When nearing menopause, menopause will cease the symptoms.

Apart from these, support from self-help groups like Endometriosis UK can beuseful when dealing with endometriosis.


How is endometriosis diagnosed

A gynaecologist will diagnose endometriosis based on the history and examination. If they suspect endometriosis, a diagnostic laparoscopy will be offered. A biopsy will be taken during laparoscopy if endometrial lesions are seen during the laparoscopy.

How can I prevent endometriosis

Currently there are no prevention strategies for endometriosis. According to World Health Organization (WHO), enhanced awareness and early diagnosis and management of symptoms may halt the progression of the disease. This will also help to reduce the long-term symptoms. Management may slow or halt the natural progression of the disease and reduce the long-term burden of its symptoms, including the risk of central nervous system pain sensitisation. Who are at risk of endometriosis

Hopkins Medicine has identified the following risk factors that can contribute to the development of endometriosis:

  • Family members, a mother, sister or daughter with endometriosis
  • Abnormal womb
  • Early beginning of periods (before 11 years)
  • Shorter durations in between periods (less than 27 days)
  • Heavy periods lasting more than 7 days

Some factors reduce the risk of developing endometriosis:

  • Breastfeeding and pregnancy
  • Late onset of the first period (after 14 years of age)
  • Consumption of fruits, especially citrus fruits

When should I see a doctor

If experiencing symptoms of endometriosis, such as pain or infertility, that are interfering with daily life, it is recommended to schedule an appointment with a GP. During the appointment, a doctor or nurse will take a medical history and perform a physical examination.


Endometriosis is a chronic condition that affects women of reproductive age and is caused by the presence of endometrial tissues outside the uterus, resulting in inflammation, scarring, and painful cysts. Despite the various hypotheses, the exact cause of endometriosis remains unknown. Common symptoms include pelvic pain, fatigue, irregular periods, heavy menstrual bleeding, and infertility. A diagnosis can be made through laparoscopy, and treatment options include pain relief medication, hormone therapy, surgery, and lifestyle changes. Given the average diagnosis time of 7.5 years, it is important for women experiencing symptoms to seek medical attention promptly to receive a proper diagnosis and treatment..


  1. Tsamantioti, Eleni S., and Heba Mahdy. ‘Endometriosis’. StatPearls, StatPearls Publishing, 2023. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK567777/.
  2. Endometriosis - statpearls - NCBI bookshelf [Internet]. [cited 2023Mar15]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK567777/ 
  3. Boucher, Astrid, et al. ‘Implantation Failure in Endometriosis Patients: Etiopathogenesis’. Journal of Clinical Medicine, vol. 11, no. 18, Sept. 2022, p. 5366. PubMed Central, https://doi.org/10.3390/jcm11185366
  4. Halme, J., et al. ‘Retrograde Menstruation in Healthy Women and in Patients with Endometriosis’. Obstetrics and Gynecology, vol. 64, no. 2, Aug. 1984, pp. 151–54
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Nipuni Rajapaksha

Bachelor of Medicine and Bachelor of Surgery (MBBS) from Rajarata University of Sri Lanka,
MSc Health Data Science for Applied Precision Medicine from the University of Dundee, UK

I am Nipuni, currently working the field of health data analysis. Earlier I worked as a Doctor, where I gained a vast amount of experience and knowledge regarding clinical conditions, patient management and communication.
I am passionate about sharing my clinical experiences in a way that everyone can understand and get information about the conditions and diseases which bother them.

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