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Endometriosis
Endometriosis affects approximately 10% of women of reproductive age in the UK. The condition can cause debilitating pelvic pain, painful periods, and difficulty conceiving. Whilst the exact causes remain incompletely understood, research suggests genetic factors contribute to susceptibility alongside hormonal and immune influences.
Overview
Endometriosis occurs when tissue resembling the endometrium - the inner lining of the womb - establishes itself in locations outside the uterus, most commonly on the ovaries, fallopian tubes, and pelvic peritoneum. This misplaced tissue responds to monthly hormonal changes in much the same way as normal endometrial tissue, leading to inflammation, scarring, and the formation of adhesions over time. The condition typically manifests during the reproductive years and may improve after menopause when oestrogen levels decline.
Endometriosis represents a significant cause of chronic pelvic pain and subfertility in women. The severity of symptoms does not always correlate with the extent of disease visible during surgical examination - some women with widespread endometriosis experience minimal discomfort, whilst others with limited visible disease report substantial pain. Diagnosis often involves considerable delay, with many women experiencing symptoms for several years before receiving confirmation of the condition.
Symptoms & clinical features
The hallmark symptom of endometriosis is pelvic pain, which often intensifies during menstruation but may persist throughout the menstrual cycle. Many women report dysmenorrhoea - painful periods that may be severe enough to interfere with daily activities, work, and education. Pain during or after sexual intercourse (dyspareunia) is another common feature, as is discomfort during bowel movements or urination, particularly during menstrual periods.
Fertility difficulties affect a substantial proportion of women with endometriosis, with some discovering the condition only during investigations for difficulty conceiving. Additional symptoms may include chronic lower back pain, fatigue, bloating, and in some cases bowel or bladder symptoms if endometriotic tissue affects these organs. The cyclical nature of symptoms - worsening around menstruation - often provides an important diagnostic clue. Some women experience no symptoms at all and discover endometriosis incidentally during surgery for other reasons.
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Affected organs
Endometriosis most frequently affects structures within the pelvis. The ovaries commonly develop endometriotic cysts known as endometriomas or 'chocolate cysts' due to their characteristic dark, blood-filled appearance. The peritoneum lining the pelvic cavity, the ligaments supporting the uterus, and the space between the uterus and rectum (pouch of Douglas) are other typical sites of involvement.
In some cases, endometriosis extends beyond the pelvic cavity to affect the bowel, bladder, ureters, or more rarely distant sites including the lungs or surgical scars. Deep infiltrating endometriosis describes disease that penetrates more than 5mm beneath the peritoneal surface, potentially causing more severe symptoms and requiring specialist surgical expertise for management.
Risks & severity
Endometriosis exists on a spectrum from minimal disease with few symptoms to severe, extensive involvement causing significant pain and organ dysfunction. Classification systems attempt to stage the disease based on the location, depth, and extent of endometriotic implants, but these stages correlate imperfectly with symptom severity or fertility outcomes.
The condition carries recognised impacts on quality of life, including effects on relationships, mental health, education, and employment. Chronic pain may lead to sleep disturbance, anxiety, and depression. Fertility concerns affect many women, though the precise relationship between endometriosis and subfertility remains complex - not all women with endometriosis experience difficulty conceiving, and treatments do not always restore fertility. Long-term complications can include chronic pelvic pain syndrome, bowel or bladder dysfunction if these organs are affected, and in rare cases an increased risk of certain ovarian cancers, although absolute risks remain low.
Genetic causes
Endometriosis demonstrates familial clustering, with first-degree relatives of affected women having a several-fold increased risk of developing the condition themselves, suggesting genetic susceptibility plays a role. However, endometriosis follows a complex, polygenic inheritance pattern rather than resulting from pathogenic variants in a single gene. Multiple genetic factors interact with environmental and hormonal influences to determine individual risk.
Research has identified several genes associated with endometriosis susceptibility. ESR1 encodes a receptor molecule that mediates cellular responses to oestrogen in reproductive tissues - variation in this gene may alter how tissues react to hormonal signals. WNT4 produces a signalling protein important for female reproductive tract development and endometrial function, with certain variants linked to elevated disease risk. GREB1 participates in cellular responses to oestrogen and helps regulate tissue growth and structural organisation within the endometrium. Variants across these genes and many others identified through large-scale studies each contribute modest individual effects that together influence a person's susceptibility, though none functions as a sole deterministic cause.
Inheritance pattern
Endometriosis does not follow a straightforward inheritance pattern like conditions caused by pathogenic variants in a single gene. Instead, it demonstrates complex genetic susceptibility influenced by multiple genes, each contributing a modest effect. Having a mother or sister with endometriosis increases a woman's own risk several-fold compared to the general population, but most women with affected relatives will not develop the condition, and many women with endometriosis have no known family history.
The polygenic nature means that genetic risk cannot be predicted through standard single-gene testing, and the condition does not segregate in families according to Mendelian ratios. Environmental factors, immune function, and hormonal influences interact with genetic predisposition to determine whether endometriosis develops. Genetic counselling for endometriosis typically focuses on explaining familial risk patterns rather than offering predictive testing.
Diagnosis & testing
Definitive diagnosis of endometriosis traditionally requires direct visualisation of endometriotic tissue, typically achieved through laparoscopy - a surgical procedure performed under general anaesthesia involving insertion of a camera through small abdominal incisions. During laparoscopy, the surgeon can identify characteristic lesions and, if appropriate, obtain biopsies for histological confirmation or perform therapeutic procedures to remove visible disease.
Increasingly, gynaecologists may make a clinical diagnosis based on characteristic symptoms and examination findings, particularly where imaging reveals suggestive features such as ovarian endometriomas on ultrasound or deeply infiltrating disease on MRI. This approach, endorsed by recent clinical guidelines, allows women to access treatment without necessarily undergoing surgery, though laparoscopy remains important for cases where diagnosis is uncertain or symptoms persist despite treatment. Blood tests and standard imaging cannot rule out endometriosis. In the NHS, women typically access investigation through GP referral to gynaecology services, with specialist endometriosis centres available for complex cases.
Management & lifestyle
Management of endometriosis aims to control symptoms, preserve or restore fertility where desired, and improve quality of life, with treatment tailored to individual circumstances, symptom severity, and reproductive goals. Hormonal treatments form a mainstay of medical management - combined oral contraceptives, progestogens, and gonadotropin-releasing hormone analogues can suppress endometrial tissue growth and reduce pain, though these approaches prevent pregnancy and symptoms often recur after stopping treatment.
Surgical options range from ablation or excision of visible endometriotic lesions during laparoscopy to, in severe cases affecting quality of life substantially, hysterectomy with or without removal of the ovaries. Surgery may improve pain and fertility outcomes for some women, though recurrence remains common. Analgesia, physiotherapy, psychological support, and complementary approaches may help manage chronic pain. NHS England has established specialist endometriosis centres providing multidisciplinary care for complex cases. Women experiencing fertility difficulties may benefit from assisted conception techniques. Management decisions involve careful discussion with gynaecology teams and specialist endometriosis nurses who can provide ongoing support and coordinate care.
UK care pathway
Women with suspected endometriosis typically enter the NHS care pathway through their GP, who may initiate initial management or refer to gynaecology services depending on symptom severity and examination findings. NICE guideline NG73 provides the framework for endometriosis investigation and management in England. Some areas operate direct-access pelvic pain clinics. Women with complex disease, severe symptoms unresponsive to initial treatments, or deep infiltrating endometriosis affecting bowel or bladder may be referred to specialist endometriosis centres accredited by the British Society for Gynaecological Endoscopy.
Genetic testing does not form part of routine endometriosis care, as the condition follows complex inheritance and no single-gene causes have been established. However, women with strong family histories or those concerned about familial risk patterns may discuss these concerns with their gynaecology team. Support organisations including Endometriosis UK provide patient information, peer support networks, and advocacy for improving access to timely diagnosis and treatment.
Frequently asked questions
Will endometriosis prevent me from having children?
Not necessarily - many women with endometriosis conceive naturally without difficulty. However, the condition is associated with reduced fertility in some cases, and the relationship between disease severity and fertility outcomes is not straightforward. If you are experiencing difficulty conceiving, your GP can refer you to fertility services for assessment and discussion of treatment options.
Does endometriosis run in families?
Endometriosis does show familial clustering - women whose mothers or sisters have the condition face a several-fold increased risk compared to the general population. However, most women with affected relatives do not develop endometriosis themselves, and many women with the condition have no family history. The genetic contribution is complex, involving multiple genes rather than a single inherited cause.
Will a hysterectomy cure my endometriosis?
Hysterectomy (removal of the womb) may help control symptoms, particularly if adenomyosis coexists, but does not guarantee cure because endometriotic tissue outside the uterus may persist. The decision involves careful discussion of risks, benefits, fertility wishes, and alternative options with your gynaecology team. Some women continue to experience symptoms even after hysterectomy, particularly if endometriotic tissue on other pelvic structures was not removed.
Can lifestyle changes help manage endometriosis symptoms?
Some women report symptom improvement with regular exercise, stress management techniques, and adequate sleep, though these approaches work best alongside medical treatments rather than as replacements. Evidence for specific interventions remains observational and limited. You should discuss any significant lifestyle changes with your healthcare team to ensure they complement your overall management plan.
How long does it typically take to get diagnosed with endometriosis?
Diagnosis often involves considerable delay, with many women experiencing symptoms for several years before receiving confirmation. This delay may occur because symptoms overlap with other common conditions and definitive diagnosis traditionally required surgical visualisation. Recent clinical guidelines now support making a diagnosis based on symptoms and examination findings in some cases, which may help reduce delays in accessing treatment.
References
- Koninckx PR, Fernandes R, Ussia A. Pathogenesis Based Diagnosis and Treatment of Endometriosis. Frontiers in endocrinology. 2021. PMID: 34899597
- Bonavina G, Taylor HS. Endometriosis-associated infertility: From pathophysiology to tailored treatment. Frontiers in endocrinology. 2022. PMID: 36387918
- Osmanlıoğlu Ş, Sanlier N. The relationship between endometriosis and diet. Human fertility (Cambridge, England). 2023. PMID: 34706611
- Mehedintu C, Plotogea MN, Ionescu S. Endometriosis still a challenge. Journal of medicine and life. 2014. PMID: 25408753
- Shim JY, Laufer MR. Adolescent Endometriosis: An Update. Journal of pediatric and adolescent gynecology. 2020. PMID: 31812704
- Parasar P, Ozcan P, Terry KL. Endometriosis: Epidemiology, Diagnosis and Clinical Management. Current obstetrics and gynecology reports. 2017. PMID: 29276652
- Xu T, Zhang H, Zhu Z. Telocytes and endometriosis. Archives of gynecology and obstetrics. 2023. PMID: 35668319
- Kajiyama H, Suzuki S, Yoshihara M. Endometriosis and cancer. Free radical biology & medicine. 2019. PMID: 30562557