Why do bowel symptoms worsen during my period?

It’s common for bowel symptoms to flare around your period because hormonal shifts can change how the bowel moves and how sensitive the pelvic nerves are. If you have endometriosis, those same shifts can amplify inflammation and pain. Endometriosis can affect the bowel directly (often the rectum/rectosigmoid) or irritate the tissues around it, so symptoms can feel gastrointestinal even when the issue isn’t primarily inside the bowel. Scarring and tethering can also pull on the bowel as the uterus contracts during menstruation, making cramping, constipation/diarrhea swings, bloating, or pain with bowel movements more noticeable.

A cyclical pattern (especially pain with bowel movements during bleeding, rectal pressure, or rectal bleeding that tracks with your cycle) raises our suspicion for bowel involvement or deep disease behind the uterus. This also explains why some people have a normal colonoscopy yet still have significant symptoms: endometriosis often affects the outer bowel surface or deeper layers rather than the inner lining a scope evaluates. If your symptoms are period-linked or progressively worsening, our team can help map what’s going on and talk through next-step evaluation and treatment options, including minimally invasive excision when appropriate.