What is Endometriosis? Nine Years to a Diagnosis

"Period pain is normal."

I heard some version of that sentence for years. From GPs who offered stronger painkillers instead of investigation. From relatives who said their periods were bad too. From a medical system that has, for too long, treated pain in women as a baseline expectation rather than a symptom to be taken seriously.

Endometriosis is not bad period pain. It is a whole-body disease.

And in the UK, it takes an average of eight years and ten months from first reporting symptoms to being diagnosed — a figure that has actually got worse since 2020, according to Endometriosis UK's 2024 survey of over 4,000 diagnosed patients. Mine took nine years. I know women from the endo community who waited far longer.

What Endometriosis Actually Is

Endometriosis is a condition where tissue similar to the lining of the uterus grows outside the uterus — on the ovaries, fallopian tubes, and elsewhere in the pelvis, and sometimes beyond it (World Health Organization, 2025). This tissue responds to the hormonal cycle much as the uterine lining does. But unlike the uterine lining, it has nowhere to go.

The result is inflammation, scarring, and adhesions — tissue that binds organs together where they should be separate. Sometimes cysts on the ovaries. And for many of us, pain that is not simply menstrual but present at other points in the cycle too.

The symptoms recognised by the WHO extend well beyond pelvic pain: severe period pain, heavy bleeding, pain during sex, pain with bowel movements or urination, bloating, nausea, fatigue, and sometimes depression and anxiety alongside it all (WHO, 2025). In my experience, the fatigue and the brain fog were as disabling as the pain — and the bowel symptoms meant I spent a stretch of time being treated for IBS before anyone looked further.

Endometriosis can also make it harder to become pregnant (WHO, 2025). I want to say this carefully, because it is so often delivered as either a promise or a threat: it is a recognised cause of difficulty conceiving, and it is also true that many people with endometriosis do conceive. If fertility matters to you, that is a conversation for your gynaecology team, with your actual scan results in front of them — not something to absorb as a verdict from the internet.

It affects roughly 10% of women and girls of reproductive age worldwide — around 190 million people (WHO, 2025). It is not rare. It is just poorly served.

Why Diagnosis Takes So Long

Diagnosing endometriosis is genuinely not straightforward. There is no blood test for it. For a long time, the definitive diagnosis was laparoscopic surgery — a camera inserted into the abdomen to look directly at the tissue — and many of us were told nothing could be confirmed without it.

That has been changing. The updated NICE guideline (NG73, updated 2024) now recommends offering a transvaginal ultrasound to people with suspected endometriosis, with specialist ultrasound or MRI for suspected deep disease — and the European guideline body ESHRE said in its 2022 guideline that laparoscopy is no longer the automatic gold standard, with imaging now the first-line assessment. But a normal scan does not rule endometriosis out — NICE is explicit that laparoscopy can still be considered even when imaging is normal (NICE NG73, 2024). That last part matters, because I had normal scans for years.

The delay is not only procedural, though. It is also cultural.

Pain in women is consistently underestimated. Research on emergency care has found that women with acute abdominal pain were less likely than men to receive pain relief and waited longer for it (Chen and colleagues, Academic Emergency Medicine, 2008), and a large 2024 study across emergency departments found the same pattern — women scored as having less pain and given fewer analgesics than men with comparable complaints (Guzikevits and colleagues, PNAS, 2024). In Endometriosis UK's 2024 survey, 78% of people who were later diagnosed said a doctor had told them they were making a "fuss about nothing" or similar — and 20% had seen a gynaecologist ten or more times before getting a diagnosis.

The normalisation of menstrual pain — the "just bad periods" dismissal — meant I didn't push for years, because I'd been told there was nothing to push for.

We all can tap into a bodily intuition. We know ourselves, and we know when something doesn't feel right. By the time I got my diagnosis, I had seen multiple specialists, collected several incorrect labels, and felt oddly guilty for having pushed as hard as I'd had to.

The Nervous System Piece

What is less widely understood is that endometriosis is not only a gynaecological condition. Over time, chronic pain changes how the nervous system processes pain.

Central sensitisation — the nervous system becoming progressively more reactive, so pain is felt more intensely and triggered more easily — is a documented process in endometriosis-associated pain (it has been the subject of a systematic review in the Journal of Pain Research, 2019). This is not "in your head" in the dismissive sense. It is a neurological adaptation to years of persistent input.

It is also part of why endometriosis pain does not always resolve completely with surgery. Surgery can remove the lesions, but it does not directly treat a sensitised nervous system. A 2023 study in JAMA Network Open followed 239 people through endometriosis surgery and found that those with higher central sensitisation scores beforehand had worse pain outcomes afterwards (Orr and colleagues, 2023).

Then there is the pattern I can only speak to from lived experience and from years inside patient communities: endometriosis so often seems to travel with other conditions — hypermobility, sleep problems like UARS, PMDD, trauma histories. This clustering is my observation and interpretation, not established science; researchers are still working out how and whether these threads connect. What I can tell you is that in my own body, and in the stories I hear again and again, they tend to arrive together, they make each other worse, and they are almost never treated together.

What I Want You to Know

If you have been told your pain is normal, and you know it isn't — keep asking. You are allowed to go back, and go back again.

If you have been treated for IBS, or depression, or anxiety, and something has never quite fit — it may be worth asking your GP whether endometriosis has been considered. NICE's updated guideline means an ultrasound referral is now a reasonable first step, not a favour you have to earn.

If you have endometriosis and you're still struggling after surgery, that is not failure, and it is not rare. The nervous system may need different support than the surgeon can provide — pain management, pelvic physiotherapy, and other options are things to raise with your gynaecology team.

And if you have endometriosis alongside other conditions — PMDD, UARS, chronic fatigue, a trauma history — please know that, at least in my world, this combination is not unusual. You are not a collection of bad luck. You are one person with an overloaded system, and looking at the whole picture matters.

Not a doctor. Personal experience and research — work with a healthcare provider for your own situation. For more on conditions that frequently co-occur with endometriosis, see Conditions.

Sources and review

I last reviewed and fact-checked this post on 19 August 2026. The general claims here lean on: the World Health Organization's endometriosis fact sheet (updated 2025) for the definition, symptoms, fertility and prevalence figures; Endometriosis UK's 2024 diagnosis survey report for the UK diagnostic delay and patient-experience figures; the NICE guideline NG73 on endometriosis diagnosis and management (updated 2024) and the ESHRE endometriosis guideline (2022) for how diagnosis now works; Chen and colleagues (Academic Emergency Medicine, 2008) and Guzikevits and colleagues (PNAS, 2024) on how women's pain is treated in emergency care; and, on central sensitisation, a systematic review in the Journal of Pain Research (2019) and Orr and colleagues' study in JAMA Network Open (2023). Everything about conditions clustering together — endo alongside UARS, hypermobility, PMDD and trauma — plus my nine-year road to diagnosis, is my own experience and interpretation, not settled research. Please take your own situation to your own gynaecology team.