If you feel like you need to pee during a colonoscopy, you won’t be able to get up and use the bathroom. The good news: most people are sedated enough that they either don’t notice the urge or don’t remember it afterward. And even if you did lose a small amount of urine during the procedure, the medical team has seen it countless times and is fully prepared.
Why You Might Feel the Urge
The colon and the bladder are close neighbors in your pelvis, separated by only a thin layer of tissue. During a colonoscopy, the scope passes through the sigmoid colon, which sits right next to the bladder. As the scope moves and loops through this area, it can physically press against the bladder wall. That pressure mimics the same signal your body sends when your bladder is actually full, creating an urge to urinate even when there isn’t much urine there.
On top of that, you’re receiving IV fluids throughout the procedure. The typical volume given during a colonoscopy is around 325 milliliters, with some patients receiving up to 1,000 milliliters. Combined with whatever was left in your system after the prep (which involves drinking large amounts of liquid), your bladder may genuinely be filling during the 20 to 45 minutes you’re on the table. The bowel prep itself often leaves people mildly dehydrated, which is exactly why the IV fluids are given, but they do end up in your bladder eventually.
What Actually Happens if You Need to Go
Most colonoscopies are performed under moderate or deep sedation. Under moderate sedation (sometimes called “twilight”), you’re in a drowsy, relaxed state where you may be vaguely aware of sensations but unlikely to act on them. Under deeper sedation with propofol, which is increasingly common, you’re essentially asleep and won’t register the urge at all. Many people wake up in recovery with no memory of the procedure, let alone any bladder discomfort.
If you’re having a colonoscopy with minimal or no sedation (which is rare in the U.S. but more common in some other countries), you might feel the urge more distinctly. In that case, the medical team can sometimes briefly pause to let you use a bedpan or urinal without removing the scope entirely. But this is unusual. The scope is a long, flexible instrument that has been carefully guided through your colon, and removing it means starting over from the beginning. That’s why the team strongly prefers to complete the procedure in one pass.
If a small amount of urine leaks during the procedure, it simply gets absorbed by the disposable pads and draping already placed beneath you for exactly this kind of situation. Colonoscopy teams deal with far messier realities on a daily basis. A little urine doesn’t register as noteworthy to them.
How to Reduce the Chance It’s a Problem
The single most helpful thing you can do is empty your bladder right before the procedure. When you arrive at the facility and change into your gown, use the bathroom one last time. Many nurses will remind you to do this, but if they don’t, take the initiative. Your bladder won’t be completely empty for the entire procedure because of the IV fluids, but starting from zero gives you a much larger window.
If you have a condition that already makes urination difficult or frequent, like an enlarged prostate, overactive bladder, or a history of urinary retention, mention it to your care team beforehand. They can plan accordingly. In rare cases, a catheter can be placed before the procedure begins, though this is typically reserved for longer or more complex endoscopic procedures rather than routine screening colonoscopies.
Bladder Discomfort After the Procedure
Some people find it temporarily harder to urinate in the hours after a colonoscopy. This is called urinary retention, and it happens because sedation medications can relax the bladder muscles and temporarily interfere with the nerve signals that coordinate urination. Among patients undergoing outpatient general surgical procedures, about 3.8% experience this. For procedures involving the anorectal area specifically, the rate can be higher, ranging from 1% to 52% depending on the type of surgery, though a straightforward colonoscopy sits at the lower end of that spectrum.
If you haven’t been able to urinate within a few hours of getting home and you feel increasing pressure or discomfort in your lower abdomen, contact your doctor’s office. Retention after sedation is temporary and very treatable, but it shouldn’t be ignored. Most people, though, find the opposite is true: the combination of IV fluids and lingering prep effects means they need to urinate frequently for the rest of the day.
The Short Version
You’ll be sedated, you probably won’t notice, and the medical team is prepared either way. Empty your bladder before the procedure starts, and you’ve done everything you can. The rest is their job, and they handle it routinely.