Bowel symptoms are incredibly common in patients with endometriosis, but determining why those symptoms are happening is not always straightforward. At Pacific Endometriosis and Pelvic Surgery (PEPS), we frequently see patients who have spent years being told they may have IBS, constipation, or food sensitivities before anyone considers the possibility of endometriosis. In reality, bowel symptoms in endometriosis can arise from several different mechanisms. Some patients have actual endometriosis lesions involving the bowel itself, while others experience bowel dysfunction related to pelvic inflammation or pelvic floor muscle dysfunction. Often, more than one process is contributing at the same time.

Bowel lesions of endometriosis most commonly affect the rectum and sigmoid colon, though lesions can occur elsewhere in the gastrointestinal tract as well. Symptoms may include pain with bowel movements, especially during menstruation, bloating, constipation, pelvic pressure, or a sensation of incomplete evacuation. Rectal bleeding due to full-thickness bowel endometriosis (involving the inner lining of the bowel) can also occur, but is quite uncommon. More often, bleeding is related to hemorrhoids or irritation associated with constipation and pelvic floor dysfunction. When the small bowel is involved, symptoms can look different and may include severe nausea, early satiety, or difficulty tolerating normal-sized meals.

Importantly, not all GI symptoms in endometriosis patients are caused by lesions directly growing on the bowel. Endometriosis creates an inflammatory environment throughout the pelvis and abdomen, and that inflammation alone can significantly disrupt gastrointestinal function. We often see bloating and bowel irregularity improve after excision surgery, even in patients without actual bowel lesions. Pelvic floor dysfunction can also contribute substantially to bowel symptoms, which is why collaboration with skilled pelvic floor physical therapists is an important part of comprehensive care.

When bowel endometriosis is suspected, imaging studies such as transvaginal ultrasound (performed by someone experienced with endometriosis) or MRI can often identify lesions before surgery, though the full extent of disease is frequently only determined intraoperatively. The surgical approach depends on how deeply the endometriosis infiltrates the bowel wall. Superficial lesions on the outer surface, or serosa, of the bowel can often be excised without entering the bowel itself. Deeper lesions may require shaving or partial-thickness excision, while disease that extends through the full thickness of the bowel wall requires full-thickness excision or segmental bowel resection. At Pacific Endometriosis and Pelvic Surgery, segmental resections are performed in collaboration with a general surgeon, who meets with patients in consultation prior to surgery when imaging suggests disease that may require segmental resection.

Because surgical findings are not always predictable ahead of time, our initial consultations at PEPS focus heavily on education and preparation so patients understand the range of possibilities before surgery. Most importantly, we want patients to understand how bowel