What you can expect

During the exam

Wearing a gown, you'll begin the exam lying on your left side on the exam table, usually with your knees drawn toward your abdomen. The doctor will insert a sigmoidoscope into your rectum.

The sigmoidoscope contains a light and a tube that allows the doctor to place air into your colon. The air expands the colon, which provides a better view of the colon lining. When the scope is moved or air is introduced, you may feel abdominal cramping or the urge to move your bowels.

The sigmoidoscope also contains a tiny video camera at its tip. The camera sends images to an external monitor so that the doctor can study the inside of your colon. The doctor can also insert instruments through the scope to take tissue samples.

A flexible sigmoidoscopy exam typically takes about 15 minutes. It may require slightly more time if biopsies are taken. Sedation and pain medications usually aren't necessary. If a polyp is found, your doctor will likely recommend a full colonoscopy to look at your whole colon, as other polyps may be present further up in the colon.

After the exam

After the exam, you may have mild abdominal discomfort. You may feel bloated or pass gas for a few hours as you clear the air from your colon. Walking may help relieve any discomfort. You should be able to return to your usual diet and activities right away.

You may also notice a small amount of blood with your first bowel movement after the exam, which usually isn't cause for alarm. Consult your doctor if you continue to pass blood or blood clots or if you have persistent abdominal pain or a fever of 100 F (37.8 C) or higher.