Endometriosis

Definition

Endometriosis is a chronic gynecologic condition characterized by the presence of endometrial-like tissue outside the uterine cavity, leading to pain, infertility, and inflammation.

Epidemiology

• Affects 6–10% of women of reproductive age globally.
• Most common in women aged 25–35 years.
• Up to 30–50% of women with infertility may have endometriosis.
• Delay in diagnosis is common, often 7–10 years from symptom onset.
• Family history increases risk; first-degree relatives are at higher risk.

Etiology

• Retrograde menstruation leading to implantation of endometrial tissue outside the uterus.
• Coelomic metaplasia or differentiation of peritoneal cells into endometrial tissue.
• Immune dysfunction allowing ectopic tissue survival.
• Genetic predisposition: certain gene variants associated with higher risk.
• Environmental and hormonal factors may contribute.

Pathophysiology

• Ectopic endometrial tissue responds to hormonal cycles, causing bleeding, inflammation, and fibrosis.
• Chronic inflammation leads to adhesion formation and pelvic scarring.
• Prostaglandins, cytokines, and growth factors contribute to pain and infertility.
• Altered immune response permits survival and growth of ectopic implants.
• Lesions may invade ovaries, fallopian tubes, peritoneum, and other pelvic structures.