• Endometriosis is a common and potentially painful, debilitating estrogen-dependent gynecologic condition predominately affecting women of reproductive age.
  • Symptoms and signs generally consist of pelvic and/or abdominal pain, pelvic mass, and/or decreased fertility.
  • Due to estrogen-dependent implants of endometrial tissue found outside the uterus; although endometriomas have been recorded in liver, bowel, umbilicus, lung, and other tissue, the most common pathologic sites are:
    • Peritoneum (bladder, cul-de-sac, pelvic walls, ligaments, and fallopian tubes)
    • Ovaries
    • Rectovaginal septum
  • Ectopic endometrial implants proliferate and slough with the menstrual cycle.
  • Stage I (minimal) to IV (severe). Staging is useful in therapeutic planning but does not correlate with pain severity.



  • Biologic females only
  • Affects 6–10% of fertile women
  • Found in 21–40% of infertile women
  • Found in 70–90% of women with chronic pelvic pain

Pediatric Considerations
Endometriosis may begin with puberty, as endometrial implants are dependent on ovarian hormones. This can lead to debilitating pelvic pain and severe dysmenorrhea associated with missed school and family/social activities.

Pregnancy Considerations
The presence of endometriosis decreases fecundability from 15–20% per month to 2–10% per month. 21–40% of infertile women have endometriosis. However, pelvic endometriosis generally improves during pregnancy.

Geriatric Considerations
Although menopause often results in a resolution of symptoms, pelvic endometriosis may extend into menopause and may be exacerbated by hormone replacement therapy (HRT).

Etiology and Pathophysiology

  • Not fully understood; several factors are believed to play a role, including immunologic changes and genetic predisposition in the presence of abnormal proliferating endometrial tissue implants causing chronic peritoneal inflammation.
  • Theories include:
    • Sampson theory: Retrograde menstruation results in peritoneal implantation and disease.
    • Halban theory: Distant disease is probably caused by hematogenous/lymphatic dissemination or metaplastic transformation.
    • Coelomic metaplasia: Coelomic epithelium remains undifferentiated in the peritoneal cavity and differentiates to form functioning endometrium.
  • Endometrial-associated infertility is multifactorial:
    • Pelvic inflammation
    • Anatomic disruption of pelvic structures (Involvement of the fallopian tube may cause isthmic tubal obstruction.)
    • Proliferation and activation of peritoneal macrophages (may predispose to gamete phagocytosis)
    • Alteration in eutopic endometrium

Odds ratio of symptomatic endometriosis with a first-degree affected relative is 7.2. Those with affected first-degree relatives have a 26% chance of severe manifestations versus 12% if no first-degree affected relatives.

Risk Factors

  • Family history
  • Prolonged lifetime exposure to menstruation and ovulation (early menarche, late menopause)
  • Delayed childbirth/nulliparity
  • Low body mass index
  • Prolonged menstruation (>5 days)/shorter menstrual cycles (<28 days)

General Prevention

  • Suppression of heavy menstruation and ovulation with oral contraceptives during adolescence may delay sequelae.
  • Some factors are considered protective:
    • Fruits, green vegetables, n-3 long-chain fatty acids
    • Regular aerobic exercise (>4 hours per week)
  • Early diagnosis and treatment might help prevent sequelae.

Commonly Associated Conditions

Infertility, dysmenorrhea, ovarian cysts, dyspareunia, chronic abdominal/pelvic pain syndrome, pelvic inflammatory disease, and irritable bowel disease

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