Causes

For many people, there is more than one cause of fecal incontinence.

Causes can include:

• Muscle damage. Injury to the rings of muscle at the end of the rectum (anal sphincter) may make it difficult to hold stool back properly. This kind of damage can occur during childbirth, especially if you have an episiotomy or forceps are used during delivery.
• Nerve damage. Injury to the nerves that sense stool in the rectum or those that control the anal sphincter can lead to fecal incontinence. The nerve damage can be caused by childbirth, constant straining during bowel movements, spinal cord injury or a stroke. Some diseases, such as diabetes and multiple sclerosis, also can affect these nerves and cause damage that leads to fecal incontinence.
• Constipation. Chronic constipation may cause a dry, hard mass of stool (impacted stool) to form in the rectum and become too large to pass. The muscles of the rectum and intestines stretch and eventually weaken, allowing watery stool from farther up the digestive tract to move around the impacted stool and leak out. Chronic constipation may also cause nerve damage that leads to fecal incontinence.
• Diarrhea. Solid stool is easier to retain in the rectum than is loose stool, so the loose stools of diarrhea can cause or worsen fecal incontinence.
• Hemorrhoids. When the veins in your rectum swell, causing hemorrhoids, this keeps your anus from closing completely, which can allow stool to leak out.
• Loss of storage capacity in the rectum. Normally, the rectum stretches to accommodate stool. If your rectum is scarred or stiff due to surgery, radiation treatment or inflammatory bowel disease, the rectum can't stretch as much as it needs to, and excess stool can leak out.
• Surgery. Surgery to treat enlarged veins in the rectum or anus (hemorrhoids), as well as more-complex operations involving the rectum and anus, can cause muscle and nerve damage that leads to fecal incontinence.
• Rectal prolapse. Fecal incontinence can be a result of this condition, in which the rectum drops down into the anus. The stretching of the rectal sphincter by prolapse damages the nerves that control the rectal sphincter. The longer this persists, the less likely the nerves and muscles will recover.
• Rectocele. In women, fecal incontinence can occur if the rectum protrudes through the vagina.