Skip to content
Condition

Endometriosis

Not bad period pain — a disease, and one that takes seven years to name

Last reviewed
July 2026
Version
1.0
Review cadence
Annually

What it is

Endometriosis is a chronic inflammatory disease in which tissue resembling the lining of the uterus grows outside it — on the ovaries, the pelvic peritoneum, the bowel, the bladder, occasionally further afield. It affects roughly 1 in 10 women and people with a uterus of reproductive age, which makes it about as common as asthma or diabetes. It causes severe period pain, chronic pelvic pain, pain during sex, pain on opening the bowels, cyclical bowel and bladder symptoms, fatigue, and subfertility. It is not 'bad periods'. It is a disease, and it takes an average of seven to eight years to diagnose — one of the worst diagnostic delays in medicine.

Why it matters

Because the delay is not a resource problem, it is a knowledge and attitude problem, and both are fixable. Two beliefs cause most of it. The first is that severe period pain is normal — which means the symptom is not reported, and when it is reported it is not investigated. The second is far more damaging and is held by clinicians as often as patients: THAT A NORMAL SCAN RULES IT OUT. It does not. Superficial peritoneal endometriosis, the commonest form, is INVISIBLE ON ULTRASOUND AND MRI. A normal scan excludes endometriomas and deep disease; it excludes nothing else. Every year of delay is a year of pain treated as a personality trait, and for some, a year of fertility.

The evidence

What BioSignal knows about treating this

Guideline-anchored clinical contextLast reviewed July 2026 · reviewed annually · 5 references

What works for Endometriosis

BioSignal’s clinical summary, most important first.

  1. TAKE THE PAIN SERIOUSLY AND GET ASSESSED — period pain that stops you living your life is not normal and is not a threshold to be endured. This is the intervention that shortens the seven-year delay, and nothing further on this list happens without it
  2. DO NOT ACCEPT 'YOUR SCAN WAS NORMAL' AS A DIAGNOSIS OF EXCLUSION — the commonest form of endometriosis is invisible on every scan that exists. A normal ultrasound rules out endometriomas. It does not rule out endometriosis
  3. Analgesia — NSAIDs are first-line for pain and are more effective than paracetamol here
  4. Hormonal suppression to stop or lighten periods: the combined pill taken continuously, progestogens, or the levonorgestrel intrauterine system. These do not cure the disease, but they suppress the cyclical stimulation that drives the pain, and they work for many people
  5. GnRH agonists with add-back therapy — for disease not controlled by first-line hormonal treatment, under specialist care
  6. Surgical EXCISION of endometriosis by a specialist centre — the evidence favours excision, and outcomes depend heavily on surgical expertise. This is a referral worth insisting on
  7. Fertility care where conception is the goal — endometriosis is associated with subfertility, and hormonal suppression is contraceptive, so the treatment plan changes completely if pregnancy is wanted
  8. Multidisciplinary chronic pain support — endometriosis pain can persist after the lesions are treated, because chronic pain rewires the pain system. Saying so is not saying the pain is imaginary
Start Here

New to this? Read these first

  1. FoundationHormonal HealthHow to read hormones properly — and why both over-treatment and under-treatment cause harm.
  2. BiomarkerFerritinIron stores — with an inflammation caveat
  3. Signal RecordCurcumin (Turmeric)The principal curcuminoid of Curcuma longa
  4. Body SystemHormonesEndocrine signaling that regulates the whole body.
  5. ConditionHeavy Menstrual BleedingNot something to put up with — and sometimes a bleeding disorder nobody looked for
Typical Journey

How this usually unfolds

  1. Recognize risk factors
  2. Get diagnosed
  3. Track key biomarkers
  4. Lifestyle first
  5. Evidence-based treatment
  6. Long-term monitoring

An orientation to how this topic is typically approached — not medical advice.

Who is at risk

  • Family history — a first-degree relative with endometriosis substantially raises risk
  • Early menarche and short menstrual cycles
  • Nulliparity
  • Prolonged exposure to menstruation (more cycles over a lifetime)
  • Heavy or prolonged menstrual bleeding
  • NOTE: there is no lifestyle cause, and nothing the person did brought this on. It is not caused by stress, by diet, or by 'not relaxing enough'

How it's diagnosed

Endometriosis is diagnosed on the SYMPTOM PATTERN first, and imaging second — and this order matters enormously, because the historical order was the reverse and it produced the seven-year delay. The pattern is cyclical, worsening pain: period pain that stops you working or studying, chronic pelvic pain, deep pain with sex, pain on defecation or urination that is worse around the period, and subfertility. Transvaginal ultrasound and MRI can identify endometriomas and deep infiltrating disease — but a NORMAL scan does not exclude endometriosis, because the commonest (superficial peritoneal) form cannot be seen on any scan. Laparoscopy was long treated as the mandatory gold standard; current guidance is explicit that treatment should NOT be delayed while waiting for it. Empirical treatment is legitimate and is often the fastest route to relief.

  • Symptom history — the primary diagnostic tool, and the one most often skipped
  • A pain and symptom diary tied to the menstrual cycle
  • Transvaginal ultrasound — identifies endometriomas and some deep disease. A NORMAL SCAN DOES NOT EXCLUDE THE DISEASE
  • MRI — for mapping deep infiltrating disease before surgery
  • Laparoscopy with excision and histology — definitive, but no longer a prerequisite for starting treatment
  • Ferritin — heavy bleeding frequently coexists, and iron deficiency is common and treatable
  • NOTE: there is no blood test for endometriosis. Any test marketed as one is not diagnostic.
Most important

Key biomarkers

Day to day

Lifestyle

  • Nothing here causes endometriosis, and nothing here cures it — but pain management, sleep and gentle activity genuinely help people live with it
  • Track symptoms against the cycle: it is the most useful thing you can bring to an appointment
  • Heat, and NSAIDs started BEFORE the pain peaks rather than after, are more effective than most people are told
  • Iron: heavy bleeding and endometriosis frequently travel together, and iron deficiency compounds the fatigue
Explore

Explore this condition across BioSignal

Frequently asked questions

Is severe period pain normal?

No. Period pain that is manageable with over-the-counter painkillers and does not stop you doing things is common. Pain that makes you vomit, that keeps you off work or school, that no painkiller touches, or that has you lying on the floor is NOT normal, and it is not a threshold of endurance you are supposed to meet. It is a symptom. The single most common reason endometriosis takes seven years to diagnose is that this pain is reported late — and then normalised when it is reported. If that describes you, it is worth being specific with a clinician: not 'my periods are bad', but 'my period pain stops me working'.

My scan was normal. Does that mean I don't have endometriosis?

No, and this is the most consequential misunderstanding in the whole area — held by clinicians as often as by patients. The most common form of endometriosis is superficial peritoneal disease, and it is INVISIBLE on ultrasound and on MRI. Scans are good at finding endometriomas (cysts on the ovary) and deep infiltrating disease. They cannot see the rest. So a normal scan rules out those things and rules out nothing else. If your symptom pattern fits endometriosis and your scan was normal, the correct next step is not reassurance — it is a conversation about treatment or referral.

Will pregnancy cure my endometriosis?

No. This is one of the most persistent and most harmful pieces of advice given to people with this disease. Symptoms often improve DURING pregnancy, because periods stop — and they very commonly return afterwards. Pregnancy is not a treatment for endometriosis, and telling someone in severe pain to have a baby is not medical advice. It has also, historically, been given to people who could not conceive precisely because of the disease.

Will a hysterectomy cure it?

Not necessarily, and this surprises people. Endometriosis is tissue OUTSIDE the uterus — so removing the uterus does not remove the disease. Hysterectomy can help where adenomyosis (endometrial tissue within the muscle of the uterine wall) is a major driver, or where bleeding is the dominant problem. But endometriosis on the peritoneum, bowel or ovaries remains behind unless it is also excised. People have had hysterectomies expecting a cure and been devastated when the pain continued.

Does endometriosis cause infertility?

It is associated with subfertility, but it is not a sentence, and many people with endometriosis conceive without help. The relationship is not simple: severe disease can distort the pelvic anatomy, but even superficial disease is associated with reduced fertility for reasons not fully understood. What matters practically is this: hormonal treatment for endometriosis works by suppressing the cycle, and is therefore contraceptive. If you are trying to conceive, the treatment plan is a different conversation — and it should be started earlier rather than later, because time matters.

Is endometriosis linked to cancer?

There is a small increase in the risk of certain ovarian cancers (clear cell and endometrioid subtypes) in people with endometriosis. The word doing the work in that sentence is SMALL: the absolute risk remains low, the great majority of people with endometriosis will never develop ovarian cancer, and this is not a reason for alarm. It is a reason to be honest, and to take persistent new symptoms seriously rather than assuming everything is 'just the endo'.

Evidence summary

Endometriosis is a chronic inflammatory disease affecting roughly 10% of women and people with a uterus of reproductive age, with a mean diagnostic delay internationally of seven to eight years. Symptom severity correlates POORLY with the extent of disease seen at surgery — a person with minimal visible disease can be in extreme pain, and extensive disease can be near-silent, which is one reason imaging-led diagnosis fails. Normal transvaginal ultrasound and MRI do NOT exclude endometriosis, because superficial peritoneal disease is not visible on either; current guidance explicitly states that treatment should not be delayed pending diagnostic laparoscopy. Hormonal suppression (continuous combined oral contraception, progestogens, the levonorgestrel intrauterine system, GnRH agonists with add-back) reduces pain in randomized evidence but is suppressive rather than curative and is contraceptive. Surgical excision by experienced surgeons improves pain and, in some, fertility; outcomes are strongly operator-dependent. Endometriosis is associated with subfertility and with a small absolute increase in clear cell and endometrioid ovarian cancer risk. There is no validated blood test and no evidence that pregnancy or hysterectomy reliably cures the disease.

References & sources

  • NICE NG73 — Endometriosis: diagnosis and management
  • ESHRE — Guideline on the management of endometriosis
  • Cochrane reviews of hormonal and surgical treatment for endometriosis-associated pain
  • Cohort studies of diagnostic delay in endometriosis
  • Studies of endometriosis and ovarian cancer subtype risk

Educational information — not medical advice

Condition pages orient you across the evidence; they don't diagnose or treat. Diagnosis and management belong with a qualified clinician. See our Medical Disclaimer.

Is this condition page clear, accurate, and useful? Your feedback shapes what we review next.

Give feedback