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How do you know if endometriosis has spread to bowel?

Endometriosis is a condition where tissue similar to the lining of the uterus grows outside of the uterus, most commonly on the ovaries, fallopian tubes, and tissue around the uterus. This tissue responds to hormones in the same way the lining of the uterus does – it thickens, breaks down, and bleeds each month. When endometrial tissue grows on the bowel, it is called bowel endometriosis. This can cause a variety of symptoms and complications. Knowing the signs and symptoms of bowel involvement can help guide diagnosis and treatment.

What are the symptoms of bowel endometriosis?

Some common symptoms of bowel endometriosis include:

  • Painful bowel movements, especially during menstruation
  • Constipation and bloating
  • Diarrhea, rectal bleeding, or blood in the stool
  • Cramping during bowel movements
  • Abdominal pain that worsens during menstruation
  • Pain during sexual intercourse
  • Nausea and vomiting

The location of the pain can help identify if the bowel is involved. Pain on the left side of abdomen may indicate disease in the rectum or sigmoid colon. Pain in the right lower abdomen may signal ileum or cecum involvement.

Some patients have no bowel symptoms at all, and bowel endometriosis is found unexpectedly during surgery for other indications. The severity of symptoms does not always correlate with the extent of bowel involvement. Even small lesions can cause significant pain.

What tests help diagnose bowel endometriosis?

If bowel endometriosis is suspected, several tests can help confirm the diagnosis:

  • Pelvic exam – May reveal nodules or tenderness involving the bowel.
  • Transvaginal ultrasound – Can identify endometrial lesions on the bowel surface in some cases.
  • MRI – Provides detailed images of the pelvis and can detect thickening of bowel walls caused by endometrial growths.
  • Colonoscopy – Directly visualizes lesions in the rectum and bowel.
  • Laparoscopy – The gold standard for diagnosis, provides visual confirmation of endometriosis implants and adhesions.

Blood tests like CA-125 are generally not helpful in diagnosing bowel endometriosis specifically. The combination of symptoms, imaging studies, and laparoscopy offer the best diagnostic accuracy.

What are the complications of bowel endometriosis?

Several complications can occur when endometriosis infiltrates the bowel:

  • Bowel obstruction – Scar tissue and lesions may partially or completely obstruct the intestinal tract.
  • Fistulas – Abnormal connections may form between the bowel and reproductive organs, like the vagina or bladder.
  • Bleeding – Lesions that penetrate deeper into bowel walls can erode into blood vessels and cause intestinal bleeding.
  • Bowel perforation – Very rarely, endometrial implants can weaken the bowel wall and cause life-threatening perforation and peritonitis.
  • Loss of bowel function – Sphincter muscles can be damaged by lesions, resulting in fecal incontinence.

Prompt diagnosis is key to prevent progression of the disease and dangerous complications. Any symptoms of intestinal obstruction, severe rectal bleeding, or fecal incontinence should be urgently evaluated.

How is bowel endometriosis treated?

Treating bowel endometriosis requires expert gynecologic and colorectal surgeons working together. Treatment options include:

  • Hormone therapy – Drugs like birth control pills, progesterone, and GnRH agonists can temporarily suppress growth of lesions.
  • Surgery – Conservative shaving of lesions or bowel resection to remove disease may be done laparoscopically or, rarely, through open abdominal surgery.

The risks and benefits of medical versus surgical options depend on the extent of disease and the patient’s symptoms. Mild lesions may respond to hormones alone, while larger growths often require excision. Recurrence rates are higher with hormone therapy. Close monitoring and follow-up care are essential regardless of treatment path.

Some key factors surgeons consider when planning surgery include:

  • Location of lesions
  • Depth of bowel involvement
  • Degree of obstruction or damage to bowel
  • Fertility desires of the patient

When bowel resection is needed, this is usually done laparoscopically through small incisions. In skilled hands, resection poses low risk of leakage and preserves bowel function very well. Temporary or permanent colostomy may rarely be needed for complicated disease.

What is the outlook for bowel endometriosis?

Many patients with bowel endometriosis can achieve significant symptom relief and enhanced quality of life with proper treatment. However, endometriosis is a chronic condition. Without surgery, hormone therapy only pauses rather than cures endometrial implants, which tend to recur over time.

After surgery, endometriosis recurrence rates are:

  • 21-43% at 2 years
  • 40-50% at 5 years

Regular follow-up monitoring for recurring symptoms allows for early retreatment. A multidisciplinary approach with gynecology, colorectal surgery, pelvic rehab, nutrition, and pain management provides optimal care. Patients with bowel involvement should be treated at specialized endometriosis centers.

While bowel endometriosis presents challenges, a proper individualized treatment plan can successfully control symptoms and inflammation, prevent complications, and preserve fertility and bowel function. With expert care, most patients can go on to live full lives despite this disease.


Endometriosis involving the bowel can produce difficult symptoms like painful bowel movements, constipation, diarrhea, and abdominal pain. A combination of imaging studies and laparoscopic visualization offer the best means of diagnosis. Hormones and conservative excision surgery are effective treatments, but require an experienced team given the risks of bowel complications. Regular follow-up is important as recurrence is common. In the hands of expert surgeons, most patients with bowel endometriosis can obtain substantial relief of their symptoms and avoid severe complications through prompt diagnosis and treatment. With proper long-term management, bowel endometriosis does not have to define or limit a woman’s life.