Endometriosis
Summary
Endometriosis is a chronic inflammatory condition characterised by the presence of endometrial-like tissue outside the uterine cavity. It affects approximately 10% of reproductive-age women and is a leading cause of chronic pelvic pain, dysmenorrhoea, dyspareunia, and subfertility. Common sites include the ovaries (endometriomas/"chocolate cysts"), pouch of Douglas, uterosacral ligaments, and pelvic peritoneum. Diagnosis is clinical/suspected based on symptoms but confirmed definitively by laparoscopy. Management depends on symptoms and fertility wishes: medical options include hormonal suppression (combined pill, progestogens, GnRH agonists); surgical options include laparoscopic excision or ablation. Endometriosis significantly impacts quality of life and requires multidisciplinary management.
Key Facts
- Prevalence: ~10% of reproductive-age women; 25-50% of women with infertility
- Sites: Ovaries (endometriomas); Pouch of Douglas; Uterosacral ligaments; Rectovaginal septum; Bladder; Bowel
- Symptoms: Chronic pelvic pain; Dysmenorrhoea; Dyspareunia; Subfertility; Cyclical symptoms
- Diagnosis: Clinical suspicion; Confirmed by laparoscopy + histology
- Staging: rASRM (revised American Society for Reproductive Medicine) I-IV
- Treatment: Analgesia; Hormonal suppression; Laparoscopic surgery; IVF for infertility
- Average diagnosis delay: 7-10 years from symptom onset
Clinical Pearls
"If She Has Cyclical Pain, Think Endometriosis": Any cyclical pelvic pain, especially with dysmenorrhoea, dyspareunia, or bowel/bladder symptoms around menses, should raise suspicion of endometriosis.
"Chocolate Cysts = Endometriomas": Ovarian endometriomas contain old blood ("chocolate" appearance). Ultrasound shows ground-glass echogenicity. Do NOT rupture during surgery (spill causes further endometriosis).
"Normal Scan Doesn't Exclude Endometriosis": Ultrasound may be normal, especially with superficial peritoneal disease. Laparoscopy is the gold standard for diagnosis.
"Excision > Ablation": Laparoscopic excision is preferred over ablation for better long-term outcomes and lower recurrence.
"Fertility Considerations Drive Management": In women wanting pregnancy, avoid prolonged hormonal suppression (doesn't treat infertility). Surgery or IVF may be needed.
Why This Matters Clinically
Endometriosis is common, debilitating, and underdiagnosed. Its impact on quality of life, mental health, and fertility is profound. Early recognition and appropriate referral can reduce the significant diagnostic delay and improve outcomes.[1,2]
Incidence & Prevalence
| Parameter | Data |
|---|---|
| Prevalence | ~10% of reproductive-age women |
| Infertile women | 25-50% have endometriosis |
| Chronic pelvic pain | 70% have endometriosis |
| Asymptomatic | Some women are asymptomatic (incidental finding) |
Risk Factors
| Factor | Effect |
|---|---|
| Early menarche | ↑ Risk |
| Short menstrual cycles | ↑ Risk |
| Family history | 7x increased risk in first-degree relatives |
| Nulliparity | ↑ Risk |
| Outflow obstruction | ↑ Risk (retrograde menstruation) |
| Increased oestrogen exposure | ↑ Risk |
Theories of Origin
| Theory | Mechanism |
|---|---|
| Retrograde menstruation | Most widely accepted; Menstrual tissue passes through fallopian tubes into pelvis |
| Coelomic metaplasia | Peritoneal cells transform into endometrial tissue |
| Lymphatic/Vascular spread | Explains distant sites (e.g., lungs, brain) |
| Stem cell theory | Circulating stem cells implant and differentiate |
Pathological Features
| Feature | Description |
|---|---|
| Ectopic tissue | Endometrial glands and stroma outside uterus |
| Hormone responsive | Proliferates in response to oestrogen; Bleeds with menses |
| Inflammatory response | Activates macrophages; Produces cytokines; Causes adhesions |
| Fibrosis | Repeated bleeding → Fibrosis and scarring |
| Endometrioma formation | Ovarian cystic collections of old blood ("chocolate cyst") |
Symptoms
| Symptom | Frequency | Notes |
|---|---|---|
| Dysmenorrhoea | 80% | Often severe; Progressive |
| Chronic pelvic pain | 70% | Non-cyclical component |
| Dyspareunia | 40-50% | Deep; Positional |
| Subfertility | 30-50% | May be presenting complaint |
| Cyclical bowel symptoms | Variable | Dyschezia; Rectal bleeding; Constipation |
| Cyclical urinary symptoms | Variable | Dysuria; Haematuria |
| Fatigue | Common | Chronic pain impact |
Signs
| Sign | Notes |
|---|---|
| Often normal | Especially with superficial disease |
| Tenderness | Uterosacral ligaments; Pouch of Douglas |
| Nodules | Palpable in rectovaginal septum or uterosacral ligaments |
| Fixed retroverted uterus | Adhesions |
| Adnexal mass | Endometrioma |
Red Flags
[!CAUTION]
- Bowel obstruction symptoms
- Ureteric involvement (hydronephrosis on imaging)
- Rapidly enlarging ovarian mass (exclude malignancy)
- Severe symptoms not responding to treatment
Pelvic Examination
| Component | Findings |
|---|---|
| Speculum | Usually normal; May see cervical lesions |
| Bimanual | Tenderness; Nodules in uterosacral ligaments; Fixed uterus; Adnexal mass |
| Rectovaginal | Nodules palpable in rectovaginal septum (deep infiltrating endometriosis) |
General Examination
- Usually normal
- Assess for signs of anaemia (heavy/prolonged menses)
Imaging
| Modality | Findings | Notes |
|---|---|---|
| Transvaginal USS | Endometriomas (ground-glass echogenicity); Kissing ovaries; Deep nodules | First-line; But may miss superficial disease |
| MRI Pelvis | Deep infiltrating endometriosis; Bladder/bowel involvement | Pre-operative planning for complex surgery |
Blood Tests
| Test | Notes |
|---|---|
| CA-125 | May be elevated; NOT diagnostic (non-specific); May monitor treatment response |
| FBC | Check for anaemia |
Definitive Diagnosis
| Investigation | Notes |
|---|---|
| Laparoscopy | Gold standard for diagnosis; Visualise lesions; Take biopsies |
| Histology | Endometrial glands and stroma confirm diagnosis |
rASRM Staging
| Stage | Description |
|---|---|
| I (Minimal) | Isolated implants; No significant adhesions |
| II (Mild) | Superficial implants <5 cm; No significant adhesions |
| III (Moderate) | Deep implants; Small endometriomas; Mild adhesions |
| IV (Severe) | Large endometriomas; Dense adhesions; Extensive disease |
Management Algorithm
ENDOMETRIOSIS MANAGEMENT
↓
┌───────────────────────────────────────────────────────────┐
│ SUSPECTED ENDOMETRIOSIS │
├───────────────────────────────────────────────────────────┤
│ Clinical suspicion (dysmenorrhoea, pelvic pain, etc.) │
│ ➤ Transvaginal ultrasound │
│ ➤ Consider MRI if deep infiltrating disease suspected │
│ ➤ Trial of empirical treatment if low suspicion of │
│ alternative diagnosis │
└───────────────────────────────────────────────────────────┘
↓
┌───────────────────────────────────────────────────────────┐
│ FERTILITY NOT DESIRED │
├───────────────────────────────────────────────────────────┤
│ FIRST-LINE: │
│ ➤ Analgesia: NSAIDs + Paracetamol │
│ ➤ Hormonal suppression: │
│ • COCP (continuous tricycle regimen) │
│ • Progestogens (oral / Mirena IUS) │
│ • GnRH agonists (+ add-back HRT to prevent bone loss) │
│ │
│ SECOND-LINE / REFRACTORY: │
│ ➤ Laparoscopic surgery (excision preferred over ablation)│
│ ➤ Hysterectomy ± BSO (definitive; selected cases) │
└───────────────────────────────────────────────────────────┘
↓
┌───────────────────────────────────────────────────────────┐
│ FERTILITY DESIRED │
├───────────────────────────────────────────────────────────┤
│ ➤ Hormonal suppression does NOT treat infertility │
│ │
│ MILD/MODERATE DISEASE: │
│ ➤ Laparoscopic excision may improve fertility │
│ ➤ Consider expectant management (natural conception) │
│ │
│ SEVERE DISEASE / FAILED CONCEPTION: │
│ ➤ IVF/ICSI │
│ ➤ Endometrioma >4 cm: Consider excision before IVF │
│ │
│ ⚠️ Avoid prolonged hormonal suppression if trying to │
│ conceive — doesn't improve fertility │
└───────────────────────────────────────────────────────────┘
↓
┌───────────────────────────────────────────────────────────┐
│ DEEP INFILTRATING ENDOMETRIOSIS │
├───────────────────────────────────────────────────────────┤
│ ➤ Multidisciplinary approach │
│ ➤ MRI for surgical planning │
│ ➤ Specialist centre referral │
│ ➤ Bowel/bladder resection may be required │
│ ➤ Ureteric stenting if obstruction │
└───────────────────────────────────────────────────────────┘
Hormonal Options
| Treatment | Mechanism | Notes |
|---|---|---|
| COCP (continuous) | Suppresses ovulation; Thins endometrium | First-line; Flexible regimens |
| Progestogens | Decidualisation; Atrophy | Oral (norethisterone); POP; Mirena IUS |
| GnRH agonists | Induced menopause | Goserelin, Leuprorelin; Add-back HRT needed if >6 months |
| GnRH antagonists | Similar to agonists | Elagolix (newer) |
| Complication | Notes |
|---|---|
| Infertility | Due to adhesions, distorted anatomy, inflammation |
| Ovarian cyst rupture/torsion | Endometrioma complications |
| Bowel obstruction | Deep infiltrating disease |
| Ureteric obstruction | Hydronephrosis |
| Chronic pain | Significant quality of life impact |
| Perioperative morbidity | Complex surgery for deep disease |
| Factor | Outcome |
|---|---|
| Recurrence after surgery | 20-40% at 5 years |
| Hormonal treatment | Suppresses symptoms; Doesn't cure or improve fertility |
| IVF success | Live birth rates similar to other causes of infertility |
| Menopause | Symptoms usually improve |
Key Guidelines
| Guideline | Organisation | Year | Key Points |
|---|---|---|---|
| Endometriosis: Diagnosis and Management (NG73) | NICE | 2017 | Diagnosis, medical and surgical management |
| ESHRE Guideline | ESHRE | 2022 | European guideline; Fertility focus |
What is endometriosis?
Endometriosis is a condition where tissue similar to the lining of the womb grows in other places, like the ovaries, bowel, or pelvis. This tissue responds to hormones and bleeds during your period, but the blood has nowhere to go, causing pain and scarring.
What are the symptoms?
- Painful periods
- Pelvic pain (especially around your period)
- Pain during or after sex
- Difficulty getting pregnant
- Bowel or bladder symptoms during your period
How is it diagnosed?
An ultrasound can sometimes show cysts, but often the only way to diagnose endometriosis for certain is with a keyhole operation (laparoscopy) where the doctor looks inside your pelvis.
How is it treated?
- Painkillers (like ibuprofen)
- Hormonal treatments (pill, coil, injections) to stop periods and slow the disease
- Surgery to remove the endometriosis tissue
- IVF if you're trying for a baby and other treatments haven't worked
Can it be cured?
Endometriosis is a long-term condition. Treatments can help control symptoms, but it often comes back. Symptoms usually improve after menopause.
- NICE. Endometriosis: diagnosis and management (NG73). 2017. nice.org.uk/guidance/ng73
High-Yield Exam Topics
| Topic | Key Points |
|---|---|
| Prevalence | 10% of reproductive women |
| Symptoms | Dysmenorrhoea, pelvic pain, dyspareunia, subfertility |
| Gold standard diagnosis | Laparoscopy + Histology |
| Treatment (no fertility wish) | Hormonal suppression; Surgery |
| Treatment (fertility wish) | Avoid prolonged hormonal suppression; Surgery; IVF |
| Endometrioma | Chocolate cyst; Ground-glass on USS |
Sample Viva Question
Q: A 28-year-old woman has severe dysmenorrhoea and dyspareunia. How would you investigate and manage suspected endometriosis?
Model Answer: I would take a detailed history including cyclical nature of symptoms, bowel/bladder symptoms, and fertility wishes. Examination: bimanual and rectovaginal for nodules and tenderness. Initial investigation: Transvaginal ultrasound to look for endometriomas (ground glass appearance) or deep infiltrating disease. MRI if complex disease suspected a
definitive diagnosis requires laparoscopy with biopsy. Management depends on fertility wishes:
- Not seeking pregnancy: Trial of COCP continuous regimen or progestogens (Mirena IUS); NSAIDs for pain. If refractory, laparoscopic excision.
- Seeking pregnancy: Hormonal suppression doesn't improve fertility. Consider laparoscopic excision for mild-moderate disease. IVF for severe disease or failed conception.
Last Reviewed: 2025-12-24 | MedVellum Editorial Team