Q. What are pelvic adhesions? Why do people with endometriosis have adhesions? A. Scarring of the peritoneum around endometriosis is a typical and very common finding. The explanation for this is that the bleeding that occurs around each menstrual cycle gets collected, and since there is no escape for this blood, it will start irritating the adjacent peritoneal surface, then start producing irritation and inflammation and eventually, scarring. These adhesions are most common in the immobile pelvic structures, and are most commonly found in the pelvic sidewalls, behind the uterus, between the sigmoid bowel or colon, and on the posterior aspect of the uterus and cervix.