Endometriosis: Why Diagnosis Takes So Long

Endometriosis affects roughly 1 in 10 women in the UK, yet the average time from first symptoms to diagnosis remains stubbornly long — often 7 to 8 years. In 2026, with gynaecology waiting lists at record levels and nearly 750,000 women waiting for care, understanding this condition and knowing how to advocate for yourself has never been more important.

What is endometriosis?

Endometriosis occurs when tissue similar to the lining of the womb grows outside the uterus — on the ovaries, fallopian tubes, bowel, bladder, and other pelvic structures. This tissue responds to hormonal changes throughout the menstrual cycle, causing inflammation, pain, and sometimes scarring. If you experience painful periods that are worsening over time, endometriosis should be considered. The condition can also coexist with adenomyosis, where similar tissue is found within the muscle wall of the uterus itself.

Why the diagnostic delay is unacceptable

Several factors contribute to the diagnostic gap, and frankly, as a gynaecologist, I find the current state of affairs deeply frustrating. Seven to eight years is not a statistic — it is the lived experience of women who are told, repeatedly, that their pain is normal. I regularly see patients in my clinic who have spent half a decade or more being prescribed paracetamol, put on the pill without a clear explanation, or referred for investigations that do not look for endometriosis specifically. By the time they reach me, many have developed chronic pain syndromes, significant psychological distress, or fertility complications that might have been avoided with earlier intervention.

• Symptom normalisation: Many women are told that severe period pain is “just normal.” It is not. Pain that prevents you from carrying out daily activities, that doesn’t respond to standard painkillers like ibuprofen 400 mg three times daily, or that worsens over time deserves investigation.
• Varied presentation: Endometriosis can cause a wide range of symptoms beyond painful periods, including deep pain during intercourse (deep dyspareunia), bowel or bladder symptoms during menstruation, chronic pelvic pain, and fertility difficulties.
• Limitations of basic scans: A standard ultrasound may not detect endometriosis, particularly superficial peritoneal disease. Specialist imaging and clinical expertise are often needed.
• Health system pressures: In the current NHS environment, referral pathways can be slow, and many women fall through the gaps between primary and secondary care.

My approach to the initial consultation

When a woman comes to see me with suspected endometriosis — whether referred by her GP or self-referred — I begin with a thorough clinical history. This is, in my opinion, the most important part of the diagnostic process. I want to understand not just the pain itself, but its character, its timing within the cycle, and how it has evolved over the years. I ask about bowel and bladder symptoms specifically, because many women do not volunteer these unless prompted. I ask about pain during sex, because this is often the symptom women are most reluctant to mention. And I ask about the impact on work, relationships, and mental health, because endometriosis is a condition that affects the whole person, not just the pelvis.

I strongly encourage patients to bring a symptom diary to their first appointment. Even a few weeks of records showing pain scores, cycle timing, and any associated bowel or urinary symptoms can be tremendously helpful. If you have had previous scans, blood tests, or surgical reports, bring those too — they save time and avoid unnecessary repetition.

The role of specialist ultrasound in diagnosis

One of the most significant advances in endometriosis care over the past decade has been the development of detailed transvaginal ultrasound (TVS) techniques specifically designed to detect deep infiltrating endometriosis. This is not the same as a standard pelvic ultrasound. In experienced hands, a specialist TVS can identify endometriomas (the “chocolate cysts” that form on the ovaries), nodules in the rectovaginal septum, uterosacral ligament involvement, bladder nodules, and bowel wall infiltration. I look for specific signs: the “sliding sign” to assess whether the uterus moves freely against the bowel (absence of this sign suggests posterior compartment adhesions), thickening of the uterosacral ligaments, and hypoechoic nodules in the rectovaginal space.

The IDEA consensus statement (International Deep Endometriosis Analysis group) provides a standardised approach to TVS reporting that I follow in my practice. When performed by a trained operator, this type of specialist ultrasound has a sensitivity of over 90 per cent for deep endometriosis — meaning that in many cases, we can make a confident diagnosis without resorting to surgery.

Clinical history versus imaging versus laparoscopy

There is still a widespread misconception that laparoscopy is required to diagnose endometriosis. While it remains the gold standard for histological confirmation — and the NICE guideline NG73 still refers to it — the reality of modern practice is more nuanced. In my endometriosis clinic, I take a layered approach. A strong clinical history combined with positive findings on specialist TVS is often sufficient to make a working diagnosis and begin treatment. Laparoscopy is reserved for cases where imaging is inconclusive but clinical suspicion remains high, where surgical excision of deep disease is planned, or where fertility assessment requires direct visualisation of the pelvis.

This matters because diagnostic laparoscopy carries its own risks — it requires a general anaesthetic, involves recovery time, and in the current NHS climate, can mean a wait of many months. If I can give a woman a diagnosis and a treatment plan based on her history and a skilled ultrasound examination, that is a far better outcome than asking her to wait another six months for surgery.

Biomarkers: where is the research heading?

One of the most frequent questions I receive is whether there will ever be a simple blood test for endometriosis. Currently, there is no validated biomarker. CA125 is sometimes measured but has poor sensitivity and specificity for endometriosis — it can be elevated in the condition but also in many other situations. Research into microRNAs, proteomics, and menstrual blood biomarkers is ongoing, and some early-phase studies have shown promise. However, we are still some way from a clinically usable diagnostic blood test. Until that day arrives, a combination of careful clinical assessment and specialist imaging remains the most reliable pathway to diagnosis.

What emerging policy changes are helping?

The Scottish Government’s Women’s Health Plan Phase Two (2026–2029) has placed endometriosis as a priority condition, with a specific goal to reduce diagnosis times. NICE guidance is being updated, and new clinical pathways are being developed to improve identification and management. The RCOG and BSGE (British Society for Gynaecological Endoscopy) continue to advocate for specialist endometriosis centres and clearer referral criteria.

How to advocate for yourself

1. Keep a detailed symptom diary recording pain levels, timing in your cycle, and impact on daily life.
2. Be specific with your GP about what you’re experiencing. Use terms like “cyclical pain,” “deep dyspareunia,” or “dyschezia” if applicable.
3. Request a specialist referral if your symptoms are significant and not improving with initial management.
4. Seek a gynaecologist experienced in endometriosis who can perform specialist ultrasound assessment and offer a comprehensive management plan.