Endometriosis is a condition that occurs when tissue similar to the endometrial tissue that lines the uterus grows in other areas of the body. It commonly develops on the pelvic organs, such as the fallopian tubes but also occurs on the bowel.
Bowel endometriosis involves the abnormal growth of endometrial tissue in the intestines.
In this article, learn more about the symptoms of bowel endometriosis, how doctors diagnose it, and what treatments are available.
Bowel endometriosis occurs when tissues similar to endometrial tissue grow on the bowel or intestine.
Endometrial tissue usually grows in the uterus to prepare the body for ovulation and possibly fertilization.
The tissue is made up of blood cells and connective and gland tissue. It thickens every month until it sheds during menstruation if fertilization does not occur.
When the tissue grows abnormally outside the uterus, such as on the bowel, the endometrial tissue still thickens in response to hormones. However, because this endometrial tissue cannot leave the body, it causes a variety of symptoms.
Doctors usually classify endometriosis as either superficial or deep. Superficial endometriosis grows on the surface of the bowel. If the tissue penetrates the bowel wall, it is called deep bowel endometriosis.
According to a 2018 review, after the genital organs, the bowel is the most common location for abnormal endometrial tissue to grow.
Symptoms of bowel endometriosis may include:
- deep pelvic pain
- pelvic pain during sexual intercourse
- painful bowel movements
- rectal bleeding (uncommon)
Abnormal endometrial tissue can grow on any segment of the bowel. But according to 2014 research, about 90 percent of the incidences of bowel endometriosis involve the rectum or sigmoid colon.
Symptoms of bowel endometriosis may vary between individuals and depend on a person's menstrual cycle.
For example, symptoms may be worse in the days leading up to menstrual bleeding.
Doctors do not know exactly why some people develop endometriosis.
One theory is that during menstruation, the blood flows back into the fallopian tubes and the pelvis. Some pieces of this tissue may attach to the lining of the bowel.
It is also possible that past surgery involving the uterus may allow the endometrial cells to attach to the incision and eventually transfer to the bowel.
Some researchers think an imbalance of estrogen may also contribute to endometriosis.
There also appears to be a genetic link. People who have a close family member, such as a mother or sister, with the condition are at an increased risk of developing endometriosis.
Researchers still do not know why endometrial tissue grows outside the reproductive organs, such as on the bowel.
Because symptoms of bowel endometriosis can mimic other intestinal problems, it is essential to rule out conditions, such as colitis, rectal tumors, and irritable bowel syndrome (IBS).
After a physical exam including a pelvic examination, a review of symptoms, and medical history, a doctor may order additional tests, including:
- an ultrasound
- a CT scan
- sigmoidoscopy to view the interior of the bowels
- laparoscopy, a surgical procedure to view the bowel and abdomen
Currently, there is no cure for endometriosis, but many treatments are available.
Treatment for bowel endometriosis may depend on how severe a person's symptoms are, their overall health, and whether they want to become pregnant.
Treatment may include the following:
If a person's symptoms are mild, a doctor may recommend managing them with over-the-counter or prescription pain medication. These drugs include acetaminophen and ibuprofen.
The medication will not stop the abnormal tissue growth but may reduce pain and discomfort.
Since estrogen plays a role in bowel endometriosis, hormone therapy may help manage the condition.
Hormonal treatment may involve taking birth control patches or pills. These medications contain estrogen, progesterone, or both and prevent the buildup of endometrial tissue. They may also shrink the growth on the bowel.
In other cases, a doctor may prescribe gonadotropin-releasing hormone, which prevents ovulation and the growth of the endometrial tissue.
The symptoms might return once a person stops taking the hormones.
A doctor may recommend surgery if hormone therapy does not ease symptoms or if a person wishes to become pregnant.
The type of surgery depends on whether the doctor classifies the condition as superficial or deep.
One procedure involves removing the endometrial tissue on the bowel but leaving the intestines intact.
If the endometrial growth is deep, a surgeon will remove the lesions and close any holes in the bowel.
In severe cases, a surgeon may remove a portion of the intestine that has endometrial tissue before reattaching the remaining sections of the bowels.
There is no conclusive evidence that a specific diet can ease symptoms of bowel endometriosis.
Some studies suggest that eating fruits and vegetables has links to fewer endometriosis symptoms.
For example, a 2018 study looked at 70,835 premenopausal women. The results indicated that women who ate one or more servings of citrus fruits daily had a 22 percent lower risk of developing endometriosis than women who consumed fewer citrus fruits. The study did not look at bowel endometriosis specifically, however.
Another small study looked at women who had IBS as well as endometriosis with bowel symptoms that worsened during menstruation.
The study indicated that eating a low FODMAP diet might ease bowel symptoms possibly associated with endometriosis.
FODMAP is the acronym for fermentable oligo-di-monosaccharides polyols.
FODMAP foods are carbohydrates that tend to trigger symptoms, such as stomach cramps, gas, and bloating.
Additional research is necessary to conclude whether a special diet can help reduce symptoms of bowel endometriosis.
The outlook for people with bowel endometriosis depends on the severity of their symptoms and the effectiveness of treatment.
Although endometriosis is a chronic condition, there are treatments, such as hormone therapy and surgery, which can help to reduce symptoms.
In many cases, symptoms of bowel endometriosis ease when estrogen levels decline after menopause.