SC Endometriosis Endometriosis Chapter 18. It can only occur after menstruation begins in a woman.
Endometriosis is very common.
Women in their 20s, 30s, and 40s are most likely to get it. Symptoms Most of the time women with endometriosis have no symptoms. The exact cause of endometriosis is unknown. One theory suggests that some of the lining of the uterus during menstruation moves backwards through the fallopian tubes into the abdominal cavity where it attaches and grows. There is also some evidence that the condition may be inherited.