Endometriosis

Endometriosis occurs when tissue resembling the endometrium—the lining inside the uterus—is found outside the uterus. Lesions are most often on pelvic structures, including the ovaries, fallopian tubes, and the lining of the pelvis, but can also occur in places such as the bowel, bladder, abdomen, or, less commonly, chest. The tissue can respond to hormonal changes and is associated with inflammation and scar tissue; adhesions may cause nearby tissues or organs to stick together. The biological processes that lead to the disease are not fully understood. Retrograde menstruation, genetic susceptibility, and immune and inflammatory processes are among the factors studied, but no single explanation accounts for every case.

Symptoms differ widely. Common problems include painful menstruation, persistent pelvic or lower-back pain, heavy menstrual bleeding, pain during sex, pain with bowel movements or urination, fatigue, and difficulty becoming pregnant. Some people have few or no noticeable symptoms. The intensity of pain does not necessarily reflect how extensive the visible lesions are, so symptoms alone do not indicate disease severity. Endometriosis can affect daily activities, mental well-being, sexual health, and fertility. The World Health Organization estimates that it affects about 10%—roughly 190 million—of reproductive-age women worldwide; it can also affect transgender men and non-binary people who menstruate.

Diagnosis can be difficult because symptoms vary and overlap with those of other conditions, and delays are common. Evaluation generally considers a person's symptoms and medical history; pelvic ultrasound or magnetic resonance imaging can help identify some forms of disease. A normal scan does not rule out every lesion. Laparoscopy, sometimes with tissue sampling, can provide direct confirmation, but the WHO and the American College of Obstetricians and Gynecologists note that surgery is not necessarily required before treatment for symptoms begins. The approach depends on clinical circumstances and the person's preferences.

There is no treatment that definitively cures endometriosis. Care is selected according to symptoms, health circumstances, treatment effects, and whether pregnancy is desired. Pain-relieving medicines and hormonal treatments are among the medical approaches used to manage symptoms; surgery may be considered in some cases to remove lesions or adhesions. Symptoms can persist or return, including after treatment. Research continues into the disease's causes, earlier diagnosis, and treatments that can address symptoms while accounting for different fertility goals.