Endometriosis: The Complete Guide to Pain, Diagnosis, Treatment and Fertility

Endometriosis affects roughly 10 percent of women and girls of reproductive age worldwide, around 190 million people, according to the World Health Organization. It can cause severe pain, heavy periods, exhaustion and difficulty getting pregnant. Yet on average it takes seven to ten years from the start of symptoms to diagnosis, often after being told again and again that painful periods are just part of being a woman. They are not, when they stop you living your life.

This guide explains what endometriosis is, the symptoms to look out for, how it is diagnosed, the treatments available, how it affects fertility, and how to manage pain and get the support you need at home, at school and at work.

What is endometriosis?

Endometriosis is a long-term inflammatory condition in which tissue similar to the lining of the womb (the endometrium) grows outside the womb. It is most commonly found on the ovaries, fallopian tubes, the lining of the pelvis (peritoneum), the ligaments behind the womb, the bowel and the bladder. Rarely, it occurs in other places such as the diaphragm, lungs or surgical scars.

Like the womb lining, this tissue responds to the hormonal changes of the menstrual cycle. It can bleed and cause inflammation, but unlike a period, the blood has no way to leave the body. Over time this leads to pain, scar tissue (adhesions) that can stick organs together, and cysts on the ovaries called endometriomas or “chocolate cysts” because of the dark old blood they contain.

Adenomyosis

Adenomyosis is a related condition in which endometrial-like tissue grows into the muscle wall of the womb. It causes heavy, painful periods and an enlarged, tender womb. It often occurs alongside endometriosis.

Who gets endometriosis?

Endometriosis can start with a girl’s first period and continue until menopause. It affects people of all ethnic backgrounds and in all countries. Transgender men and non-binary people assigned female at birth can also have endometriosis. Risk is higher if a mother or sister has it, if periods started early, if cycles are short or periods long and heavy, or if there is a blockage to menstrual flow.

What causes it?

The exact cause is not known, and it is likely that several factors combine:

• Retrograde menstruation: some menstrual blood flows backwards through the fallopian tubes into the pelvis. This happens in most women, but in some, the cells implant and grow.
• Immune system differences that fail to clear these cells
• Genetics: endometriosis runs in families, and several genetic regions have been linked to it
• Cell transformation: cells outside the womb may change into endometrial-like cells
• Spread through blood or lymph to distant sites
• Hormones: oestrogen fuels the growth of endometriosis

Endometriosis is not caused by anything a person did, and it is not a sexually transmitted infection.

Symptoms

• Painful periods (dysmenorrhoea) that affect daily life, do not respond well to usual painkillers, or get worse over time
• Chronic pelvic pain lasting six months or more, not only during periods
• Pain during or after sex (dyspareunia), often deep inside
• Painful bowel movements, especially during periods, and bloating (“endo belly”), constipation or diarrhoea
• Pain when passing urine or blood in the urine during periods
• Heavy periods or bleeding between periods
• Difficulty getting pregnant
• Fatigue, which can be severe
• Pain in the lower back, legs or shoulder tip during periods
• Low mood and anxiety, often linked to living with pain and not being believed

The severity of symptoms does not always match the amount of endometriosis. Some people with extensive disease have few symptoms, and others with small amounts have severe pain. Some have no symptoms and are diagnosed only during fertility investigations.

Is period pain normal?

Mild cramping that is eased by simple painkillers and does not stop you doing normal activities is common. Period pain that makes you miss school or work, wakes you at night, makes you vomit or faint, does not respond to anti-inflammatory painkillers, or is getting worse over time is not something you should have to accept. It deserves assessment.

Why does diagnosis take so long?

• Normalisation of period pain by families, schools and healthcare providers
• Symptoms overlapping with other conditions such as irritable bowel syndrome, urinary tract infections and pelvic inflammatory disease
• Embarrassment or stigma about discussing periods, bowels and sex
• Limited awareness among some healthcare providers
• Limited access to specialist scans and surgery in many countries
• Normal scans that are wrongly taken to mean endometriosis is not present

How endometriosis is diagnosed

Symptoms and examination

A healthcare provider will ask about your symptoms, menstrual cycle, bowel and bladder habits, and pain with sex. Keeping a pain and symptom diary for a few months is very helpful. An abdominal and, where appropriate and with consent, internal examination may reveal tenderness, nodules or a fixed womb.

Imaging

A transvaginal ultrasound by an experienced sonographer can detect endometriomas, deep endometriosis nodules and adenomyosis. MRI is useful for deep endometriosis and planning surgery. Importantly, a normal scan does not rule out endometriosis, because small superficial patches are often invisible on scans.

Laparoscopy

Laparoscopy is keyhole surgery under general anaesthetic, in which a camera is inserted through a small cut near the belly button to look inside the pelvis. Endometriosis can be seen, and samples taken for testing. It can also be removed during the same operation. International guidelines from the European Society of Human Reproduction and Embryology (ESHRE) now say that laparoscopy is no longer required to start treatment, and treatment can begin based on symptoms and imaging. Laparoscopy is still used when imaging is normal and symptoms persist, or when surgery is planned.

New tests

Researchers are developing blood and saliva tests for endometriosis. Some are available commercially in a few countries, but they are not yet recommended in routine guidelines.

Stages

Endometriosis is sometimes described in stages from 1 (minimal) to 4 (severe), based on how much is seen at surgery. Stages describe extent, not pain, and do not predict symptoms well.

Treatment options

There is no cure for endometriosis, but treatments can reduce pain, slow progression and improve fertility. Treatment depends on your symptoms, priorities, age and whether you want to become pregnant.

Pain relief

• Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen or mefenamic acid, taken at the start of pain or a day before the period is expected, work better than paracetamol for period pain. Take with food and check they are safe for you.
• Paracetamol can be combined with NSAIDs.
• Heat: hot water bottles or heat patches on the abdomen or back help many people.
• TENS machines may help some people.
• Neuropathic pain medicines such as amitriptyline may be used for chronic pelvic pain under specialist guidance.
• Long-term opioids are generally avoided because of side effects and dependence.

Hormonal treatments

Hormonal treatments reduce or stop periods and lower oestrogen activity, which can shrink endometriosis and reduce pain. They act as contraception (except some) and must be stopped to try for pregnancy.

• Combined oral contraceptive pill, often taken continuously without breaks to avoid periods
• Progestogens: progestogen-only pills such as desogestrel or dienogest, the contraceptive injection, implant, or a hormonal intrauterine device (IUD), which delivers progestogen directly to the womb
• GnRH agonists (such as goserelin or leuprorelin injections) create a temporary menopause-like state; usually given with “add-back” HRT to protect bone density and reduce menopausal symptoms
• Oral GnRH antagonists such as relugolix combination therapy (relugolix with oestradiol and norethisterone acetate), now approved in several countries for endometriosis pain

Side effects vary and can include irregular bleeding, mood changes, headaches, weight change and reduced libido. Many people try more than one treatment before finding one that suits them.

Surgery

Surgery can remove or destroy endometriosis patches and cysts and divide adhesions. It is usually done by laparoscopy. Excision (cutting out) of endometriosis is generally preferred over ablation (burning) for endometriomas. For deep endometriosis affecting the bowel, bladder or ureters, surgery should be done in a specialist endometriosis centre with a team that includes bowel and urology surgeons.

Surgery can significantly reduce pain, but symptoms return in a proportion of people within a few years, and repeated surgeries can affect ovarian reserve. Hormonal treatment after surgery can reduce recurrence.

Hysterectomy

Removal of the womb, sometimes with the ovaries, may be considered for people with severe symptoms who have completed their families and for whom other treatments have not worked. It does not guarantee a cure, as endometriosis outside the womb can persist, and removing the ovaries causes immediate menopause. It is a major decision that requires careful discussion.

Endometriosis and fertility

Endometriosis is found in a significant proportion of women with infertility, but many people with endometriosis conceive naturally. It can affect fertility by distorting the pelvic anatomy, blocking tubes, damaging ovaries and creating an inflammatory environment that affects eggs and implantation.

• If you are trying to conceive and have not succeeded after 12 months (or 6 months if you are over 35, or sooner if you have known endometriosis), seek a fertility assessment.
• Surgery to remove endometriosis may improve natural pregnancy rates in some cases.
• Surgery for endometriomas should be considered carefully, because it can reduce the number of eggs in the ovary. A test of ovarian reserve, such as AMH, may be done first.
• IVF is often an effective option.
• Hormonal treatments for endometriosis do not improve fertility and are stopped when trying to conceive.
• Some people consider freezing eggs before surgery or if fertility is a concern for the future.

Living with endometriosis

Self-management

• Track symptoms with a diary or app to spot patterns and plan around predictable bad days
• Exercise: regular gentle activity, yoga and stretching help some people with pain and mood
• Pelvic physiotherapy: specialist physiotherapists can treat pelvic floor muscle tension, which is common in people with chronic pelvic pain and painful sex
• Diet: evidence is limited, but some people find that reducing certain foods eases bowel symptoms. A low-FODMAP diet may help if symptoms overlap with irritable bowel syndrome; seek guidance from a dietitian before making major changes
• Sleep and rest: fatigue is real, so pace activities and plan rest
• Psychological support: pain management programmes, CBT and counselling can help you cope with chronic pain and its emotional impact

Sex and relationships

Painful sex can affect intimacy and relationships. Talk openly with your partner, try different positions, take time, use lubricant, and explore intimacy that does not involve penetration. Pelvic physiotherapy and psychosexual therapy can help. You do not have to put up with painful sex in silence.

Endometriosis at school and work

Endometriosis can mean missed school days and work, reduced productivity and, for some, leaving jobs altogether. Studies suggest it costs economies billions each year in lost productivity.

• Talk to a school nurse or teacher about a plan for bad days, such as access to toilets, painkillers, a rest space and flexible deadlines
• At work, consider discussing reasonable adjustments with your manager or occupational health, such as flexible hours, working from home on bad days, breaks and access to facilities
• In many countries, endometriosis that has a long-term, substantial effect on daily life may count as a disability, giving legal protection
• Some organisations now have menstrual health or menopause policies that include endometriosis

Endometriosis and other health conditions

People with endometriosis may have a higher risk of some other conditions, including irritable bowel syndrome, interstitial cystitis (painful bladder syndrome), migraine, autoimmune conditions, depression and anxiety, and possibly heart disease. Endometriosis slightly increases the risk of certain types of ovarian cancer, but the overall risk remains low. Long-term follow-up and attention to overall health are important.

Endometriosis and menopause

Symptoms often improve after menopause as oestrogen levels fall, but not always. Endometriosis can persist or, rarely, reactivate with HRT. People with a history of endometriosis who need HRT after menopause, especially after hysterectomy, are usually advised to take combined HRT (oestrogen plus progestogen) rather than oestrogen alone, to reduce the risk of reactivation.

Getting heard: tips for appointments

• Bring a symptom diary covering at least two or three cycles
• Describe how symptoms affect your life: missed school or work, cancelled plans, sleep
• Mention any family history of endometriosis
• Ask directly: “Could this be endometriosis?” and “What would rule it out?”
• Ask for a specialist ultrasound or referral to a gynaecologist if symptoms persist despite treatment
• Bring a support person if that helps
• If you do not feel listened to, ask for a second opinion

When to seek urgent help

• Sudden, severe pelvic or abdominal pain, particularly with fever, vomiting or fainting
• Pain with a positive pregnancy test (possible ectopic pregnancy)
• Very heavy bleeding soaking through a pad every hour
• Blood in the urine or stools with severe pain
• Shoulder tip pain with abdominal pain and feeling faint

The nurse’s role

Nurses in schools, sexual and reproductive health clinics, primary care and gynaecology play a vital role in recognising symptoms early, validating pain, educating young people about what is normal, and supporting referral. Specialist endometriosis nurses in many centres coordinate care, explain treatment options, support people before and after surgery, and provide a point of contact for ongoing support.

Common myths

• Myth: Period pain is always normal. Fact: Severe pain that affects daily life needs assessment.
• Myth: Pregnancy cures endometriosis. Fact: Symptoms may improve during pregnancy but often return afterwards.
• Myth: Hysterectomy always cures it. Fact: Endometriosis outside the womb may remain.
• Myth: Teenagers are too young. Fact: Endometriosis can start with the first period.
• Myth: You cannot get pregnant with endometriosis. Fact: Many people do, naturally or with treatment.

Endometriosis in teenagers

Many adults with endometriosis say their symptoms began in their teenage years. Recognising it early can prevent years of pain and disruption to education.

• Signs in teenagers include missing school regularly because of period pain, pain not helped by anti-inflammatory painkillers or the pill, pain between periods, and bowel or bladder pain during periods
• Internal examinations are not always needed; an abdominal ultrasound or MRI may be used instead of a transvaginal scan
• Treatment usually starts with anti-inflammatory painkillers and hormonal options such as the pill or progestogens
• Parents and teachers can help by believing young people and supporting them to seek care

School nurses are often the first health professionals a teenager talks to about period pain. Asking simple questions, such as how many days of school they miss and whether painkillers help, can identify those who need further assessment.

Building a pain management plan

Many people with endometriosis find that combining several approaches works better than relying on one. A personal plan might include:

• Before your period: start anti-inflammatory painkillers a day before pain is expected, if your healthcare provider agrees; prepare heat packs; plan lighter days at work or school
• During bad days: regular pain relief at the right doses, heat, rest balanced with gentle movement, relaxation or breathing techniques, and support from people around you
• Between periods: ongoing hormonal treatment if used, regular exercise, pelvic floor relaxation exercises, good sleep and stress management
• Review: if your plan is not controlling pain, return to your healthcare provider rather than struggling on

Central sensitisation and chronic pain

After years of pain, the nervous system itself can become more sensitive, a process called central sensitisation. This means pain may persist even after endometriosis has been treated, and other areas may become painful too. This is not imagined pain; it is a recognised change in how the nervous system processes signals. Treatments that calm the nervous system, such as certain medicines, pain psychology, pelvic physiotherapy and graded activity, are often needed alongside treatments aimed at endometriosis itself. Specialist pain clinics can help.

Cost and access around the world

Access to specialist scans, surgeons and newer medicines varies widely between and within countries. In many low- and middle-income countries, endometriosis is under-recognised, and costs of diagnosis and treatment fall on families. WHO has highlighted endometriosis as a public health issue and called for better awareness, earlier diagnosis and access to affordable treatment, including simple options such as anti-inflammatory painkillers and hormonal contraceptives at primary care level. Several countries, including Australia, France and the United Kingdom, have launched national endometriosis action plans or strategies in recent years.

Research to watch

Research is advancing in non-invasive diagnostic tests, including blood biomarkers and saliva tests based on small RNA molecules, as well as new non-hormonal medicines that target inflammation and pain pathways rather than oestrogen. Large genetic studies are revealing links between endometriosis and other conditions. Taking part in research, where available, can help improve care for future generations.

Frequently asked questions

Can endometriosis be seen on a normal ultrasound?

Cysts and deep nodules can be seen, especially by experienced specialists, but superficial endometriosis usually cannot. A normal scan does not rule it out.

Does endometriosis get worse over time?

It varies. In some people it progresses, in others it stays stable or improves.

Can diet cure endometriosis?

No diet cures endometriosis, but some people find dietary changes help symptoms, particularly bowel symptoms.

Is endometriosis cancer?

No. It is a benign condition, although it is linked to a small increase in the risk of some ovarian cancers.

Can men get endometriosis?

Extremely rare cases have been reported, usually linked to high-dose oestrogen treatment.

But what if I am told it is all in my head?

Your pain is real. Endometriosis is a recognised physical disease, and the long delays in diagnosis are a well-documented failure of healthcare systems, not a reflection of you. Keep a record of your symptoms, ask specific questions, and seek another opinion if you are not being heard. Advocacy organisations around the world can help you find specialists and support.

Related: Endometriosis: symptoms and diagnosis · Pelvic pain in women · Heavy periods · PCOS guide

Sources: World Health Organization (endometriosis fact sheet), European Society of Human Reproduction and Embryology (ESHRE) endometriosis guideline (2022), National Institute for Health and Care Excellence (NG73, updated 2024), American College of Obstetricians and Gynecologists, World Endometriosis Society.