Overactive Bladder Causes

Written by Rachel Nall, RN, BSN | Published on February 26, 2014
Medically Reviewed by George Krucik, MD, MBA on February 26, 2014

What Is an Overactive Bladder?

The bladder is a muscular, pear-shaped organ responsible for holding and releasing urine. The muscles in the bladder contract to cause urination. The brain controls this process.

An overactive bladder causes the bladder to contract involuntarily and unpredictably.

In some instances, this effect results in urine leakage. This occurrence is known as a “wet” overactive bladder. In other instances, there is no leakage. This is known as a “dry” overactive bladder.

Regardless of the type, the condition can lead to a sensation known as urinary urgency. This occurs when you have a sudden urge to urinate, even if you have gone to the bathroom recently.

What Causes Overactive Bladder?

Overactive bladder can have one or multiple causes. In some cases, the exact cause of overactive bladder may be unknown. Causes include:

Bladder Abnormalities

Having bladder stones or tumors can cause involuntary bladder contractions.

Damage to Bladder Nerves

Nerves in the bladder typically transmit messages to the brain when you are purposefully using the restroom. However, trauma or certain medical conditions can damage the nerves.

Traumatic injuries that can affect bladder nerves include back or pelvic surgery, a herniated disc, and radiation. Medical conditions that can affect the bladder’s nerves include diabetes, multiple sclerosis, Parkinson’s disease, and stroke.

Estrogen Deficiency

After menopause, the estrogen levels in a woman’s body drop. This can increase the urge to urinate.

Excess Fluid Intake

The bladder’s muscles work on a supply-and-demand basis. If you increase the supply by taking in lots of fluids, your bladder will need to release the excess via urination.

Excess Weight

Being overweight can place extra pressure on the bladder muscles, weakening them and leading to overactive bladder.


A bladder or urinary tract infection (UTI) can irritate the nerves in the bladder. This can stimulate the urge to urinate or cause involuntary bladder contractions.

Medications and Diuretics

Alcohol and caffeine can have a diuretic effect on the bladder. This means that they cause the bladder to fill rapidly. Medications can also affect nerve transmissions or cause the bladder to fill rapidly. This is true for diuretics such as Lasix (furosemide) or Bumex (bumetanide).

Obstruction to Urine Flow

An enlarged prostate can affect urine flow from the urinary tract. Constipation or having undergone previous operations to the urinary tract can also obstruct urine flow.

Weakened Pelvic Muscles

Pregnancy and childbirth can weaken the pelvic muscles around the bladder. This can cause it to sag or affect its position. The bladder’s opening can also stretch after childbirth, causing it to leak.

What Are the Symptoms of Overactive Bladder?

An overactive bladder can cause a variety of symptoms that affect the need and frequency of urination. Symptoms include:

  • nocturia, or the need to get up and urinate two or more times per night
  • an urgent need to urinate, especially around triggers such as running water, that you cannot control
  • urinary leakage when you feel the need to urinate
  • urinating more than eight times per day

How Is an Overactive Bladder Treated?

An overactive bladder is a common condition. It is frequently treatable. If you experience an overactive bladder, a doctor can determine if there is an underlying cause, such as infection, and prescribe appropriate treatments.

Many treatments, including diet modifications, can treat overactive bladder.

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