Endometriosis is a chronic condition where tissue similar to the lining of the womb grows in other parts of the body, most commonly in the pelvis. It affects approximately 1 in 10 women and those assigned female at birth during their reproductive years, causing pain, heavy periods and, in many cases, difficulty conceiving.
Despite affecting an estimated 190 million people worldwide, endometriosis is widely underdiagnosed. In the UK alone, around 1.5 million women are currently living with the condition, yet more than half of the general population cannot identify what it is.
This article covers the key facts about endometriosis, including how it develops, the most common symptoms, how long diagnosis typically takes in the UK, and what fertility options are available if you are affected.
If you are experiencing symptoms and want to understand your options, book a free advisory call with IVF Matters to speak with a fertility specialist.
What Is Endometriosis?
Endometriosis occurs when cells similar to the endometrium (the lining of the uterus) grow outside the womb. These cells respond to hormonal changes during the menstrual cycle, building up and breaking down like the womb lining. Because this tissue cannot leave the body, it causes inflammation, scarring, and adhesions in the surrounding areas.
The condition most commonly affects the peritoneum (the lining of the pelvis), the ovaries, the fallopian tubes, and the tissue between the vagina and rectum. In rarer cases, it can appear in the bowel, bladder, diaphragm, or lungs.
There is currently no known cure for endometriosis, and its exact cause remains unclear. Emerging research points to immune system dysregulation as a contributing factor, with higher rates of other immune-mediated conditions such as lupus and inflammatory bowel disease observed in people with endometriosis (WHO, Endometriosis Fact Sheet, October 2025)
Endometriosis Facts and Statistics
These endometriosis facts UK highlight a condition that is both widespread and poorly served by existing healthcare pathways. The 9-year diagnostic delay alone means that many women spend most of their twenties and early thirties without a diagnosis, often being told their symptoms are normal.
| Statistic | Figure | Source |
|---|---|---|
| Women affected in the UK | 1.5 million | Endometriosis UK |
| People affected worldwide | 190 million | WHO |
| Average time from first GP visit to diagnosis (UK) | 9 years and 4 months | Endometriosis UK Diagnosis Report, 2026 |
| Prevalence in women with infertility | 30 to 50% | WHO |
| Annual cost to the UK economy | £8.2 billion | Endometriosis UK |
| Ranking among UK gynecological conditions | Second most common (after fibroids) | RCOG |
Sources: WHO — Endometriosis Fact Sheet and Endometriosis UK — What Is Endometriosis?
Endometriosis Symptoms: What to Look For
The most commonly reported symptoms include:
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Severe cramping during menstruation that does not respond well to over-the-counter painkillers
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Chronic pelvic pain that persists outside of menstruation
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Heavy or prolonged menstrual bleeding
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Pain during or after sexual intercourse
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Pain during bowel movements or urination, particularly around menstruation
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Abdominal bloating and nausea
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Fatigue that is not explained by other factors
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Difficulty getting pregnant
One of the most important endometriosis awareness facts is that symptom severity does not always match disease extent. A person with a small number of endometrial lesions can experience intense pain, while someone with extensive endometriosis may have very few symptoms (Cleveland Clinic, Endometriosis, 2024).
Why Endometriosis Misdiagnosis Is So Common
The average time from first GP visit to an endometriosis diagnosis in the UK is 9 years and 4 months (Endometriosis UK Diagnosis Report, 2026). This delay is one of the most significant endometriosis facts, and it has real consequences for fertility, mental health, and quality of life.
Several factors contribute to endometriosis misdiagnosis and delayed diagnosis:
Symptom normalisation. Many women are told that painful periods are normal, particularly during adolescence. This delays when someone seeks further investigation.
Symptom overlap. Endometriosis symptoms overlap with conditions such as irritable bowel syndrome (IBS), pelvic inflammatory disease (PID), and ovarian cysts. Misdiagnosis as one of these conditions is common.
Limited awareness among healthcare professionals. Not all GPs are trained to recognise endometriosis patterns, particularly in younger patients. The condition is frequently dismissed as "just period pain" before more serious investigation is considered.
Reliance on surgical diagnosis. Historically, laparoscopy (keyhole surgery) has been the only definitive way to confirm endometriosis. Many women are reluctant to undergo surgery, and many GPs are reluctant to refer for it without strong clinical suspicion.
Non-Invasive Diagnostic Options
Advances in imaging, including transvaginal ultrasound and MRI, can now identify certain forms of endometriosis, particularly ovarian endometriomas and deep infiltrating endometriosis, without surgery.
Newer diagnostic tools are also emerging. IVF Matters offers the Ziwig Endotest®, a saliva-based endometriosis test that uses next-generation sequencing and AI analysis of salivary microRNAs to detect the condition.
The test shows 97.4% sensitivity and 93.5% specificity, including for early-stage peritoneal endometriosis that conventional imaging often misses.
Results are typically available within 2 to 3 weeks, and the test includes a complimentary clinical review with Dr Irfana Koita, Consultant Gynaecologist and Fertility Specialist at IVF Matters.
How Endometriosis Affects Fertility
Endometriosis does not automatically mean infertility. An estimated 60 to 70% of women with the condition can still conceive naturally. However, among women who experience infertility, 30 to 50% are found to have endometriosis.
The condition can affect fertility in several ways:
Fallopian tube blockage. Endometrial tissue, adhesions, or scarring can physically block the fallopian tubes, preventing the egg from meeting the sperm.
Ovarian damage. Endometriomas (cysts on the ovaries caused by endometriosis) can reduce ovarian reserve and impair egg quality.
Inflammation. The chronic inflammatory environment created by endometriosis can affect embryo implantation and early pregnancy development.
Altered pelvic anatomy. Adhesions can distort the normal positioning of the reproductive organs, interfering with egg release and transport.
If you have been trying to conceive for more than six months and either you or your partner has known endometriosis, it is worth consulting a fertility specialist. At IVF Matters, Dr Koita assesses each case individually, reviews previous investigations, and recommends a treatment pathway based on the specific presentation, rather than applying a one-size-fits-all protocol.
Fertility Treatment Options for Women With Endometriosis
Several fertility treatments can help women with endometriosis conceive, depending on the severity of the condition and the specific barriers to conception.
Ovulation induction. For mild endometriosis where the fallopian tubes are open, medication to stimulate egg release combined with timed intercourse may be a first step.
Intrauterine insemination (IUI). IUI places prepared sperm directly into the uterus, bypassing some of the barriers that mild endometriosis can create. This is usually combined with ovulation-stimulating medication.
In vitro fertilisation (IVF). For moderate to severe endometriosis, or where other treatments have been unsuccessful, IVF bypasses the fallopian tubes entirely. The egg is collected directly from the ovary, fertilised in the laboratory, and the resulting embryo is transferred to the uterus.
Surgical treatment before fertility treatment. In some cases, removing endometrial lesions, cysts, or adhesions through laparoscopic surgery before starting fertility treatment can improve outcomes. The decision to operate depends on the location, extent, and type of endometriosis.
At IVF Matters, all fertility treatments are offered as fixed-price, all-inclusive packages, so the cost of medication, monitoring scans, and laboratory procedures is known before treatment begins. Flexible payment plans are available for those who need to spread the cost.
Types of Endometriosis
Endometriosis is classified into four types based on where the tissue grows and how deep the lesions extend. You can have more than one type at the same time.
Peritoneal (superficial) endometriosis is found mainly on the peritoneum, the thin membrane that lines the inside of the pelvis. This is the most common form and can be mild or moderate.
Ovarian endometriosis (endometrioma) refers to cysts that form on one or both ovaries when endometrial tissue becomes trapped inside the ovary. These are sometimes called "chocolate cysts" because of their dark, thick fluid content.
Deep infiltrating endometriosis involves lesions that penetrate more than 5mm below the peritoneal surface. It can affect the bowel, bladder, and the tissue between the vagina and rectum, and typically causes the most severe symptoms.
Extra-pelvic endometriosis occurs outside the pelvis entirely. The most common extra-pelvic site is the thorax (chest), including the diaphragm and lungs. This form is rare but can cause chest pain or shortness of breath timed with menstruation.
Living With Endometriosis: Managing the Condition
There is no cure for endometriosis, but the symptoms can be managed with a combination of medical treatment, surgical intervention, and lifestyle adjustments.
Pain management. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are commonly used. For more severe pain, a GP or specialist may recommend stronger prescription options.
Hormonal treatment. Combined oral contraceptives, the hormonal coil (Mirena), progestins, and GnRH analogues can all be used to suppress the menstrual cycle and reduce symptom severity. These are not suitable for women currently trying to conceive.
Surgery. Laparoscopic surgery can remove endometrial lesions, adhesions, and endometriomas. In severe cases where other treatments have failed, and pregnancy is not planned, hysterectomy (with or without removal of the ovaries) may be considered, though it is not a guaranteed cure.
Multidisciplinary support. Physiotherapy, cognitive behavioural therapy (CBT), nutritional advice, and counselling can all help manage the physical and emotional burden of the condition. IVF Matters treatment packages include access to a nutritionist and counsellor as part of the fixed price.
FAQs on Facts About Endometriosis
Can Endometriosis Develop After Menopause?
It is uncommon but possible. Most endometriosis symptoms resolve after menopause because oestrogen levels decline. However, women taking hormone replacement therapy (HRT) may experience a recurrence or continuation of symptoms, since HRT reintroduces the hormonal environment that stimulates endometrial tissue growth.
Is There a Genetic Risk Factor for Endometriosis?
Research suggests a familial link. If your mother, sister, or grandmother has endometriosis, your risk of developing the condition is higher than the general population. Clinicians still study the exact genetic mechanisms, but a family history is considered a significant risk factor.
What Is the Difference Between Endometriosis and PCOS?
Endometriosis and polycystic ovary syndrome (PCOS) are both common gynaecological conditions, but they are distinct. Endometriosis involves tissue growth outside the uterus and is primarily associated with pain and inflammation. PCOS is a hormonal and metabolic condition characterised by irregular ovulation, elevated androgen levels, and multiple small follicles on the ovaries. Both can affect fertility, but the mechanisms and treatment approaches differ.
Does Diet Affect Endometriosis Symptoms?
There is no clinically proven "endometriosis diet," but some women report symptom improvement when they reduce inflammatory foods such as processed sugar, red meat, and alcohol. Increasing omega-3 fatty acids, fibre, and anti-inflammatory foods like leafy greens and oily fish may help manage inflammation. A consultation with a qualified nutritionist can help build a plan tailored to your situation.
Take the Next Step
If you suspect you may have endometriosis, or if you have been diagnosed and want to understand how it affects your fertility, speaking to a specialist is the most useful next step. Book a free advisory call with IVF Matters to discuss your symptoms, diagnostic options (including the Ziwig Endotest®), and treatment pathways. There is no obligation to proceed.
