Endometriosis is one of those health conditions that is rarely discussed, yet affects millions of women worldwide. Many suffer from it for years without knowing exactly what is happening to them, normalizing intense pain or discomfort that, in reality, shouldn’t be part of their daily lives. That’s why understanding what endometriosis is and how it manifests is a key step in seeking help, obtaining an early diagnosis, and improving quality of life.

In simple terms, endometriosis occurs when tissue similar to the lining of the uterus (the endometrium) grows outside of it. This tissue can appear on the ovaries, fallopian tubes, the outer surface of the uterus, the bladder, the intestines, and, less frequently, other parts of the body. The problem is that this “misplaced” tissue reacts to the hormonal changes of the menstrual cycle, causing inflammation, pain, and, over time, scarring or adhesions.

One of the major challenges of endometriosis is that it doesn’t always manifest in the same way. Some women with extensive lesions have few or no symptoms, while others with small areas of endometriosis suffer from very intense pain. This variability means the disease often goes unnoticed or is mistaken for other gynecological problems.

To better understand endometriosis, it’s helpful to imagine how the menstrual cycle works. Each month, the endometrium thickens to prepare for a possible pregnancy. If pregnancy doesn’t occur, the tissue sheds and is expelled during menstruation. In endometriosis, the tissue that grows outside the uterus also reacts to hormones, but it has no way to be eliminated. This causes internal inflammation, persistent pain, and, in some cases, microscopic internal bleeding that irritates nearby organs.