Bowel symptoms
by Ros Wood (Australia)

Bowel symptoms are a common but often unrecognised consequence of endometriosis, especially chronic and recurrent endometriosis. Nobody knows exactly what proportion of women with endometriosis have bowel symptoms; it could be five percent, thirty percent, or anywhere in between. However, we are fairly sure that a relatively large proportion of our members suffer from bowel symptoms of some sort.

When the American, British, and Australian endometriosis groups were set up in the early to mid 1980s, it became clear that many of their members had bowel symptoms. At the time, few doctors realised that bowel symptoms were a common symptom of endometriosis. It was only when the national endometriosis groups began talking to leading gynaecologists about the experiences of their members that doctors began to look for and find bowel symptoms in their patients.

Nowadays, most gynaecologists and many GPs understand the relationship between bowel symptoms and endometriosis. However, too many GPs still do not think of endometriosis when their young female patients report symptoms such as intermittent constipation or diarrhoea, or alternating bouts of the two. Most importantly, they do not think to ask the young woman if her bowel symptoms vary with her menstrual cycle – the key feature of bowel symptoms due to endometriosis. As a result, some young women are not being diagnosed with endometriosis.

Most bowel symptoms are not due to the presence of endometriosis on the surface of the bowel itself. Rather, they are usually due to irritation from implants and nodules located in adjacent areas, such as the Pouch of Douglas, uterosacral ligaments, and rectovaginal septum.

In those cases where the endometrial implants are located on the bowel, the implants are usually lying on the outside surface of the bowel or rectum rather than in the bowel itself. Nevertheless, endometriosis can penetrate into and through the bowel wall on some occasions. The large bowel is a much more common site of endometriosis than the small bowel.

Some bowel symptoms are due to adhesions constricting, twisting, or pulling on the bowel.

Diagnosing bowel symptoms due to endometriosis – like any tentative diagnosis of endometriosis – relies heavily on the woman's description of her symptoms and menstrual history. Bowel symptoms due to endometriosis are generally only present or are worse around the time of the period, though they may be present throughout the month. They are also usually reported along with one or more of the classical symptoms of endometriosis, such as painful periods and painful intercourse, rather than on their own.

Women whose bowel symptoms are due to endometrial nodules in the Pouch of Douglas may find a vaginal examination painful. The gynaecologist may also be able to feel nodules in the Pouch of Douglas.

Sometimes the gynaecologist will refer the woman to a bowel specialist if he or she is not sure whether the bowel symptoms are due to endometriosis or another cause. Occasionally, the gynaecologist may refer the woman to a bowel specialist for a colonoscopy. A colonoscopy is an examination of the inside of the bowel with a telescope-like instrument. In most women with endometriosis, the colonoscopy will be normal because endometrial implants and nodules rarely penetrate through the wall of the bowel wall so they are not visible during a colonoscopy.