What Are Symptoms of Endometriosis in the Bowel?

Medically Reviewed on 12/14/2022
What Are Symptoms of Endometriosis in the Bowel
Symptoms resemble those of irritable bowel syndrome although they may change with the menstrual cycle

Bowel endometriosis occurs when endometrial tissue grows on the intestines or other parts of the bowel. Symptoms resemble those of irritable bowel syndrome although they may change with the menstrual cycle, intensifying in the days before and during a period.

Symptoms of bowel endometriosis include:

Symptoms may be nonspecific, which can lead to delays in the precise diagnosis and prolongs the ill effects of the disease. The level of bowel involvement in endometriosis varies widely and so do the symptoms. If endometriosis is restricted to the outermost layer of the bowel (bowel serosa), it may not cause symptoms.

What is endometriosis?

The endometrium is the tissue lining the inside of the uterus wall. When this tissue develops anywhere outside of the uterus, the condition is known as endometriosis. Endometriosis is commonly seen in the pelvic region, affecting organs of the pelvis such as the ovaries, fallopian tubes, and other pelvic structures. Endometrium-like tissues can occasionally be detected outside of the pelvic organs.

Endometrium-like tissue behaves similarly to endometrial tissue, thickening and breaking down with each menstrual cycle. However, because this tissue cannot leave your body, it can lead to endometriomas which are cystic or fluid-filled masses that generally affect the ovaries. The surrounding tissues can become inflamed, leading to the formation of scar tissue and adhesions, which are bands of fibrous tissue that can cause pelvic tissues and organs to cling together.

Endometriosis can cause considerable discomfort, particularly during menstruation. Additionally, fertility issues may arise. 

The exact cause of endometriosis is unknown. Several theories have been proposed, however:

  • Some of the tissues may back up through the fallopian tubes into the abdomen during menstruation. These cells can implant in the pelvis or reach other places of the body through the bloodstream or lymphatics.
  • Genes may be to blame for cells converting into endometrial tissue.
  • The immune system may also be involved.


Endometriosis occurs deep inside the uterus. See Answer

What are the 4 stages of endometriosis?

Endometriosis is divided into four stages based on the amount of tissue present and the depth to which it reaches your organs:

  • Stage I (minimal): Endometriosis has formed tiny patches on or around organs in your pelvic or abdominal region.
  • Stage II (mild): The patches are larger and deeper than in stage I and may lead to scar formation.
  • Stage III (moderate): Endometriosis has many deeper implants and is associated with cysts in the ovaries and adhesions. 
  • Stage IV (severe): Endometriosis has become more widespread and is associated with deeper implants, larger ovarian cysts, and several adhesions.

What causes endometriosis in the bowel?

When endometrial tissue invades the intestine, rectum, sigmoid colon, or small bowel, the condition is known as bowel endometriosis.

Endometrial tissue can accumulate and produce cysts called endometriomas. Moreover, the surrounding tissue can become inflamed, resulting in scar tissue or adhesions that cause organs and tissues to cling together. This causes symptoms such as pain and discomfort.

There are two types of endometriosis that can impact the bowel:

  • Superficial bowel endometriosis (the surface of the bowel is affected)
  • Deep bowel endometriosis (the lesions pass through the gut wall)

Studies report that bowel endometriosis is the most common type of endometriosis outside of pelvic endometriosis. It is thought to occur in 5%-15% of all instances of endometriosis. 

Can a colonoscopy detect bowel endometriosis?

In order to confirm a diagnosis of detect bowel endometriosis, your doctor will conduct a physical examination to look for any growths in your vagina and rectum.

The following tests can assist your doctor in diagnosing bowel endometriosis:

  • Ultrasound: An ultrasound can show your doctor the size and location of the endometriosis. This test uses high-frequency sound waves to generate images of the inside of your body. A transducer is inserted into your vagina (transvaginal ultrasound) or rectum (transrectal endoscopic ultrasound).
  • MRI: This imaging technique uses strong magnets and radio waves to detect endometriosis in the intestine and other areas.
  • Barium enema: X-rays are used to capture images of your large intestine. An enema filled with a contrast dye is given prior to the X-ray. This makes it easier for your doctor to see inside your colon.
  • Colonoscopy: A flexible scope is used to inspect the interior of your large intestines during this procedure. A colonoscopy can rule out colon cancer, which can produce similar symptoms.
  • Laparoscopy: A laparoscopic procedure may be done to detect endometriosis in your abdomen and pelvis.  A narrow, illuminated scope is passed into your abdomen through small incisions on the abdominal wall. A small tissue sample is collected which is further examined in the lab to identify the type of tissue. This process is called a biopsy.

How do you get rid of bowel endometriosis?

Endometriosis is a chronic illness that can be challenging to treat, but with proper care, symptoms can be reduced. 

Pain management

This can range from over-the-counter acetaminophen and ibuprofen to stronger prescription medications such as opioids. In more severe cases, you may be sent to a pain management team.

Hormonal therapy

These therapies inhibit or prevent ovulation (the release of an egg from the ovary), allowing the endometriosis to shrink by reducing hormonal stimulation. However, hormonal therapy will not cure endometriosis, and symptoms will return if therapy is discontinued.

  • Hormonal therapies with contraception
    • A combination oral contraceptive pill or patch can be taken continuously without a pill-free interval; typically inhibits ovulation and either stops or lightens your periods temporarily.
    • An intrauterine device (IUD) can help reduce discomfort and lighten cycles; some women who use an IUD have no periods at all.
    • Progestogens in injectable, pill, or contraceptive implant form may be taken.
  • Hormonal therapies without contraception
    • Tablets containing progestogens may be taken.
    • Gonadotropin-releasing hormone agonists and antagonists are administered through injection, implant, or nasal spray. They are quite effective but can trigger menopausal symptoms such as hot flashes, night sweats, vaginal dryness, and mood swings. They have also been linked to a decrease in bone density. As a result, they are rarely used for more than 6-9 months.

Supportive treatments

Reflexology, acupuncture, and herbal treatments may help some women alleviate discomfort or enhance their quality of life. However, there is a lack of scientific evidence to support their efficacy.


The goal of surgery is to excise (cut out) or eradicate (ablate) as much endometriosis as possible. Even if all the endometriosis is removed, however, some women may have a recurrence.

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Should bowel endometriosis be removed?

There are three surgical options for bowel endometriosis depending on the depth of the intestinal involvement:

  • Rectal shave: In most cases, the endometriosis nodule may be shaved off the intestine without having to open it up. Endometriosis is removed with a laser or scissors. This may occasionally result in a tiny amount of endometriosis remaining in the intestine. If the intestinal wall is very thin or there is a tiny hole in the colon, sutures may be put in.
  • Disc resection: For deeper endometriosis nodules, a disc of the intestinal wall is removed, and the opening is repaired with sutures or staples.
  • Segmental resection: In some cases, particularly when endometriosis causes intestinal narrowing, it may be necessary to remove a segment of the colon and then perform an anastomosis (by rejoining the two ends of the gut).

Most surgeries may be performed laparoscopically, which means through 3-4 tiny incisions in your abdomen. The advantage of laparoscopic surgery is that you will heal faster and there will be less scar tissue (adhesions) formed within your abdomen. In rare cases, a laparotomy or open surgery will be required.

What are the risks of bowel endometriosis surgery?

The most significant risks of this difficult operation include:

  • Leaking of intestinal contents from where the endometriosis was removed (which can be fatal)
  • Need for a stoma, which is an opening in the abdomen that drains the bowel contents.

A rectovaginal fistula can develop in 1-2 occurrences out of 100 following a rectal shave, but after more complex bowel operations, it can develop in 10-15 cases out of 100. 

A rectovaginal fistula is a faulty connection between the rectum and vagina, which causes gas or feces to seep from the vagina. This is most likely if the vagina is accessed during surgery. To heal a fistula, further surgery and a temporary stoma are required. 

There is also the risk of urinary tract injury (bladder and ureters). During the procedure, the nerves that regulate the bladder may be injured, making it difficult to empty the bladder. Some women might require a catheter to empty their bladder for a while following surgery.

Seek immediate medical attention if you observe any of the complications following surgery:

Medically Reviewed on 12/14/2022
Image Source: Getty image

Bowel Endometriosis: https://www.webmd.com/women/endometriosis/bowel-endometriosis

Bowel Endometriosis: Current Perspectives on Diagnosis and Treatment: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6996110/

Diagnosing Bowel Endometriosis: https://nezhat.org/diagnosing-bowel-endometriosis-step-by-step-workup/