Types of MS bladder problems

MS can stop a bladder storing or holding pee like it should (an ‘overactive’ bladder). Or it might not empty properly (an ‘underactive’ bladder). Both these problems cause a range of symptoms, including urinary tract infections. Those infections can also make your MS symptoms worse.   

Doctors aren’t sure why some people get one and not the other, or why some people get a bit of both.

If everything is working as it should, bladder control is something most people tend to take for granted. When your bladder is getting full, a warning system between your brain and bladder tells you that you should go to the toilet – and you can usually ‘hold on’ until you get to one.

The muscles in the bladder need to work in coordination with each other when storing and emptying. One relaxes while the other contracts. Problems happen when something goes wrong with this system.

What causes bladder problems?

Bladder problems happen when MS causes nerve damage that stops your bladder working like it should.  Your bladder is made of muscle. Nerves in that muscle make the bladder tighten or squeeze (‘contract’). This pushes pee out when you go to the toilet.  

Other nerves in the muscle make it relax. This lets your bladder get bigger so it can store pee between visits to the toilet.  

Your bladder also has two rings of muscle around your urethra (the tube that takes your pee out of the body). These are called sphincters. One is at the neck of your bladder, where your urethra joins your bladder. The other is lower down your urethra.

Nerves in your bladder are linked to others in your lower back. These take messages from your bladder, up your spinal cord, then to your brain – and back again. If MS damages nerves in the spinal cord or certain parts of the brain, that can also affect how the bladder works.

Some people have bladder changes when they have an MS relapse. But bladder problems also become more likely the longer someone has MS. That’s because over time MS nerve damage can build up.

Storage problems: your bladder doesn’t hold pee like it should 

With bladder storage problems, the muscle in your bladder squeezes (‘contracts’) when it shouldn’t. It tries to empty when it’s not full. Even a little pee in the bladder makes it try to empty. This problem with storing pee is called an overactive bladder. It causes:

• ‘urinary urgency’ (you need to pee straight away and can’t hold on) 
• ‘urinary frequency’ (you feel the need to pee more often than is normal).  
• both urgency and frequency can cause ‘incontinence’ (you suffer from ‘leakage’ where you have bladder ‘accidents’) 
• ‘urinary hesitancy’ (you feel you need to pee but nothing happens. Or pee comes out in a weak or interrupted stream)   

Emptying problems: your bladder doesn’t empty (or ‘void) like it should 

With this problem your bladder can’t empty itself enough. The muscle in your bladder can no longer squeeze your pee out properly. Or the sphincter in your bladder doesn’t relax and open like it should. 

The flow of your pee is weak or interrupted. This means your bladder doesn’t empty as much as it needs to. A sign of this is you need to pee again a short time later.  

We normally feel the need to empty our bladder when it’s two thirds full. In a healthy bladder, after you’ve been to the toilet, about 10% of the pee gets left in it. If there’s more pee than this, it triggers your bladder. It will tell you it wants to empty again. Also, bacteria will grow in this leftover pee. This causes urinary tract infections. These can make your MS symptoms worse. They can mimic a relapse or even trigger an actual one.

This problem with not emptying properly is called an underactive bladder. It causes:  

• urgency (you can’t hold on) 
• frequency (you pee often) 
• incontinence (you leak) 
• hesitancy (you find it hard to pee) 
• you strain when you pee  
• half a minute or so after a pee, you go again (called ‘double voiding’)  
• after you’ve been to the toilet you don’t feel your bladder is really empty  
• you keep getting urinary tract infections 

Urinary tract infections

Urinary tract infections (UTIs) are common MS symptoms. That’s because nerve damage caused by MS stops your bladder emptying like it should. This leaves pee in your bladder where bacteria can grow. Read more about UTIs and MS. 

Find out about managing bladder problems

Last full review: 1 August 2026
Next review date: 1 August 2029

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