Editorial note: This article began as an AI-generated draft prepared for the Endometriosis Awareness & Education Blog. It was clinically reviewed, edited where needed, and approved for publication by Dr Amena Shelleh.
Endometriosis is a long-term condition in which tissue similar to the lining of the womb grows elsewhere in the body.
It is common. The World Health Organization estimates that endometriosis affects around 10% of women of reproductive age worldwide, representing approximately 190 million people.
Endometriosis most commonly affects structures within the pelvis, but it can sometimes occur elsewhere in the body.
Symptoms vary considerably. Some people have relatively few symptoms, while others experience pain or other problems that have a substantial effect on everyday life.
Where Can Endometriosis Occur?
Endometriosis is most commonly found within the pelvis.
It may affect areas such as:
- the ovaries
- the tissue lining the pelvis
- areas around the womb
- the bowel
- the bladder
Endometriosis can occasionally occur outside the pelvis, including in the abdomen or chest.
Endometriosis on the ovaries can sometimes form cysts called endometriomas. The condition may also be associated with inflammation and scar tissue or adhesions.
What Causes Endometriosis?
The exact cause of endometriosis is not known.
Several possible mechanisms have been investigated, involving factors such as menstruation, immune responses, genetics and the development of endometriosis-like cells.
However, there is currently no single proven explanation that accounts for every case.
Importantly, endometriosis is not caused by anything somebody has done, and it is not an infection or a form of cancer.
What Are the Symptoms?
Symptoms differ from person to person.
Common symptoms can include:
- severe period pain
- pelvic pain outside of periods
- pain during or after sex
- pain when opening the bowels
- pain when passing urine, particularly around a period
- heavy menstrual bleeding
- fatigue
- difficulty becoming pregnant
Some people may also experience digestive symptoms such as bloating or nausea.
The severity of somebody’s pain does not necessarily indicate how much endometriosis they have. Someone with relatively limited disease may experience significant pain, while another person with more extensive endometriosis may have fewer symptoms.
Who Can Develop Endometriosis?
Endometriosis most commonly affects patients assigned female at birth and people who menstruate from their teenage years through their reproductive years.
Symptoms can begin from the time periods start.
Endometriosis can also continue to cause symptoms later in life, including around and after menopause in some circumstances.
Anyone experiencing symptoms that suggest endometriosis should be assessed according to their individual circumstances rather than assuming they are too young or too old to have the condition.
Why Can Diagnosis Take So Long?
Endometriosis can be difficult to recognise because symptoms vary and can overlap with other conditions.
For example, pelvic pain and digestive symptoms may also occur with conditions such as irritable bowel syndrome, adenomyosis or fibroids.
Painful periods can also sometimes be normalised or underestimated, meaning people may live with significant symptoms before endometriosis is considered.
In March 2026, Endometriosis UK reported that the average time to receive an endometriosis diagnosis in the UK was 9 years and 4 months.
This figure comes from Endometriosis UK’s survey research and describes the experiences of its respondents. Individual diagnostic journeys vary considerably.
How Is Endometriosis Diagnosed?
There is no single test that is used in every case.
Assessment normally begins with a discussion about symptoms and medical history. A healthcare professional may also offer an abdominal or pelvic examination.
Current NICE guidance recommends offering a transvaginal ultrasound scan to people with suspected endometriosis, even when an abdominal or pelvic examination is normal.
If a transvaginal ultrasound is declined or is not suitable, a transabdominal pelvic ultrasound and occasionally a transrectal ultrasound may be considered instead.
Ultrasound can identify some forms of endometriosis, including ovarian endometriomas and some deep endometriosis.
However, an important point is that:
A normal examination or ultrasound does not rule out endometriosis.
If deep endometriosis is suspected, specialist ultrasound or MRI may sometimes be used.
What About Laparoscopy?
Laparoscopy is keyhole surgery in which a small camera is inserted through the abdomen so that a surgeon can examine the pelvis.
It can be used to diagnose endometriosis and, depending on the circumstances, treatment may be carried out during the same procedure.
However, it is no longer helpful to describe laparoscopy simply as a test that everybody must undergo before endometriosis can be recognised or managed.
NICE recommends considering diagnostic laparoscopy in appropriate circumstances, including when symptoms continue despite normal ultrasound or MRI findings.
The decision depends on the person’s symptoms, previous investigations, treatment preferences and clinical circumstances.
How Is Endometriosis Treated?
There is currently no cure for endometriosis, but treatments can help manage symptoms and their effect on everyday life.
Treatment should be individualised and may include:
- pain-relieving medicines
- hormonal treatments
- surgery
- other approaches to persistent pain
- fertility assessment or treatment when appropriate
Not everybody needs surgery.
Treatment decisions should take account of the person’s symptoms, priorities, preferences, fertility plans and the effect the condition is having on their life.
Endometriosis and Fertility
Endometriosis can be associated with difficulty becoming pregnant, but having endometriosis does not mean that somebody will necessarily be infertile.
Many people with endometriosis become pregnant without fertility treatment.
Anyone concerned about fertility should discuss their individual circumstances with an appropriate healthcare professional.
When Should You Speak to a Healthcare Professional?
Consider speaking to a GP if you have symptoms that may suggest endometriosis, particularly if they:
- interfere with everyday activities
- regularly cause absence from work or education
- affect relationships or sexual activity
- are persistent or becoming worse
- are not adequately controlled by current treatment
Keeping a pain and symptom diary can also help when discussing symptoms with a healthcare professional.
If initial treatment does not help, or symptoms continue to have a significant effect on daily life, further assessment or referral may be appropriate.
Living With Endometriosis
Endometriosis affects people differently.
For some, symptoms can be managed relatively well. For others, the condition can have a substantial effect on physical health, emotional wellbeing, relationships, work, education and fertility.
Support should therefore focus on the individual rather than assuming that everybody experiences endometriosis in the same way.
Receiving appropriate information, assessment and treatment can help people understand their symptoms and make informed decisions about their care.
Final Thoughts
Endometriosis is a real and sometimes complex medical condition.
Severe period pain or persistent pelvic pain should not automatically be dismissed as something somebody simply has to tolerate.
At the same time, symptoms can have many possible causes, so appropriate medical assessment is important.
If you are concerned that you may have endometriosis, speak to a healthcare professional and explain clearly how your symptoms affect your everyday life.
Sources and Further Reading
- NICE. Endometriosis: diagnosis and management (NG73). Recommendations on recognition, imaging, referral, pain relief and treatment; last updated 11 November 2024; accessed 5 October 2026.
- NHS. Endometriosis. Symptoms, getting help, diagnosis and treatment; accessed 5 October 2026.
- World Health Organization. Endometriosis. Fact sheet dated 15 October 2025; overview and symptoms, including the global prevalence estimate; accessed 5 October 2026.
- Endometriosis UK. The state of endometriosis care in the UK: a roadmap for driving down diagnosis times and improving access to care. Released March 2026. Survey background and diagnosis times, page 3; accessed 5 October 2026.
Disclaimer
This article is provided for general information and education only. It is not a substitute for individual medical advice, diagnosis or treatment. Anyone concerned about possible endometriosis or persistent symptoms should speak to an appropriately qualified healthcare professional.
