Endometriosis: The Uterine Disease That Affects People Without Uteruses

Understanding Endometriosis

• 💡 Endometriosis is a disease where tissue similar to the uterine lining grows outside the uterus, causing inflammation, lesions, and debilitating pain.
• 🎯 This condition affects about 11% of cis women and can also occur in individuals without a uterus, challenging traditional understandings of the disease.

The Retrograde Menstruation Hypothesis

• 🔬 The most widely accepted theory, proposed by John Sampson in 1927, suggests retrograde menstruation where menstrual flow travels backward through the fallopian tubes, carrying tissue to other parts of the body.
• ⚠️ While intuitive, this hypothesis doesn't fully explain cases in individuals who do not menstruate or lack a uterus.

Challenging the Retrograde Hypothesis

• 📌 Studies on transmasculine patients and individuals with MRKH syndrome (born without a uterus) show they can still develop endometriosis, casting doubt on retrograde menstruation as the sole cause.
• 🧩 Even in MRKH syndrome, the presence of a rudimentary uterus in many patients suggests a potential origin for the rogue tissue.

Alternative Explanations for Endometriosis

• 🚀 Metaplasia, the transformation of one cell type into another, is a newer hypothesis suggesting that mesothelial cells (which line organs) could turn into endometrial cells, potentially triggered by inflammation or hormonal changes.
• 🧬 This theory could explain endometriosis in cis men, who lack menstrual equipment, possibly due to hormonal therapy or other unknown triggers.

Current Understanding and Treatment

• 📈 While retrograde menstruation remains the most common explanation, researchers acknowledge that endometriosis might be multiple diseases or have several causes, necessitating broader research.
• ✅ Modern diagnosis often involves laparoscopy, ultrasounds, and MRIs, and treatments include hormonal contraceptives and assisted reproductive technologies like IVF, offering more options than in the past.