Chronic inflammatory condition caused by hormone-dependent growth of endometrial-like tissue outside the uterus. Deposits may be superficial or infiltrating.

demographics: Women of reproductive age

Aetiology: not fully understood ?retrograde menstruation

• Other contributing factors include:
  • Coelomic metaplasia → The coelomic (peritoneum) contains pluripotent cells that differentiated into endometrial cells during embryonic development.
  • Iatrogenic implantation → Postsurgical scars through episiotomy or laparotomy are thought to be prime locations for implantation of endometrial cells that are spread from delivery or surgical procedures.
  • Hematogenic and lymphogenic dissemination of endometrial cells
  • Hereditary component

Pathophysiology

• viable cells from retrograde menstruation → peritoneal fluid → implant, grow, and infiltrate in the peritoneal cavity
• Regardless of location, remains sensitive to oestrogen so clinical features depend on menstrual cycle
• repeated inflammation and scarring → adhesions
• Common locations of endometriotic implants include:
  • Pelvic organs
    • Ovaries: most common site; often affected bilaterally
    • Rectouterine pouch
    • Fallopian tubes
    • Bladder
    • Cervix
  • Peritoneum
  • Extrapelvic organs (e.g., lung or diaphragm): less commonly affected

Risk factors

• Nulliparity
• Prolonged exposure to endogenous estrogen (early menarche, late menopause)
• Short menstrual cycles (< 27 days)
• Menorrhagia (> 1 week)
• Family history- Individuals with an affected first-degree relative have a three- to ten-fold increased risk of endometriosis.
• greater height
• defects in uterus or fallopian tubes