Overactive Bladder (OAB)

What is an overactive bladder?

An overactive bladder (OAB) refers to a group of urinary symptoms, with the most common symptom being the sudden and uncontrolled need to urinate.

The bladder is a pelvic organ that stores urine produced by the kidneys. It can store up to around 350ml – 500ml of urine. You may be aware that your bladder is filling when it is about half full. To empty the bladder, you have to be able to relax the pelvic floor when it is a convenient time to urinate. The brain then sends a signal to the bladder to start squeezing out the urine after the pelvic floor relaxes.

How often should you urinate?

The number of times you urinate depends on certain factors such as the amount you drink. Most people should urinate less than 8 times during the day, and either not at all or once during the night. If the number of times is greater than those above, you may have lower urinary tract symptoms (LUTS). 

What are overactive bladder symptoms?

Overactive bladder symptoms are common and can affect both men and women at any age, and may become more common as we age. Between 10 to 20% of people suffer from OAB at some point in their lives. OAB symptoms are a cumulation of urinary storage symptoms including:

  • Urinary urgency — The sudden need to urinate and trouble holding the bladder before you reach the toilet.

  • Urge incontinence — Leakage or the involuntary loss of urine when one feels the urge.

  • Frequent urination — The need to urinate more often than what you would usually experience.

  • Nocturia — The need to wake up at night to urinate.

What causes overactive bladder symptoms?

Symptoms of an overactive bladder can be caused by:

  • Weak pelvic muscles

Pelvic muscles may be weakened and stretched during pregnancy and childbirth. This weakening may cause the bladder to sag out of its normal position, causing urine leakage.

  • Nerve damage/ Neurological conditions

Inconsistencies in signals between the brain, spine and bladder muscles affect the way the bladder fills or empties. Patients with neurological conditions such as stroke, Parkinson’s disease, spinal cord compression, injuries or surgeries, may experience OAB at some point in time.

  • Medication

Certain medications can interfere with the bladder or urethra’s normal functions, leading to urine leakage or frequent urination. A common medication is a diuretic (a medication prescribed for heart or kidney failure) which pushes water out of the body and hence leads to large volumes of urine and leakage when one does not reach the toilet in time.

  • Excessive alcohol and caffeine consumption

Alcohol and caffeine also irritate the bladder, worsening overactive bladder symptoms.

  • Infection

A Urinary Tract Infection (UTI) can cause an overactive bladder by increasing the activity of the bladder wall due to inflammation.

  • Being overweight

Having excess body weight may press downwards, causing pressure on the abdominal area. This, in turn, increases bladder pressure and mobility of the urethra.

  • Oestrogen deficiency

Oestrogen plays an important role in female continence. An oestrogen deficiency, often an effect of menopause, causes vaginal dryness and affects the strength of the urethra and vagina.


What complications arise from untreated OAB?

Generally, OAB symptoms are not life-threatening. However, it can disrupt your day-to-day activities and affect your overall quality of life. This may lead to:

  • Emotional distress
  • Anxiety
  • A disruption in your sleep cycle
  • Problems with sexuality


What causes overactive bladder symptoms?

OAB symptoms can have various causes:

  • Sudden and spontaneous abnormal contractions of the bladder muscles.
  • Increased sensitivity to bladder filling.
  • The kidneys produce too much urine at night, causing nocturia. This may be related to older age or certain medical conditions.
  • Smaller bladder capacity which fills up more quickly.
  • Other conditions which produce more urine than usual such as diabetes mellitus or diabetes insipidus. We may need to exclude such medical conditions before starting treatment.
  • Other conditions may behave like OAB (i.e. urinary tract infections) or lead to OAB. We may also investigate and treat these conditions.

How is OAB diagnosed?

In order to diagnose OAB, your urologist will get a detailed medical history and conduct a physical examination of your genital area. Some diagnostic tests may also be carried out.

1.   Medical history

The urologist will take a detailed medical history and ask questions about your symptoms. You may be asked the following questions:

  • Describe the current symptoms
  • Duration of symptoms
  • List of the current medications
  • Previous surgical procedures undergone
  • Other diseases or conditions
  • Lifestyle (exercising, smoking, alcohol, and diet)


2.   Physical examination

The urologist will do a general physical examination on:

  • Abdomen
  • Genitals
  • Back and lower limbs


3.   Investigations

  • Urine test
    Samples of your urine are taken to test for urinary tract infections or traces of blood in the urine.

  • Bladder diary
    You may be asked to keep a bladder diary over 3 days where you will need to keep track of the amount you drink, how often you urinate and how much urine is produced. This helps your doctor understand your symptoms better. You may be asked to buy a measurement jug if you do not have one.

  • Uroflowmetry
    This is a simple test that electronically records the rate of urine flow. You will urinate into a container, called a uroflowmeter. This test helps your doctor to check whether there is any obstruction to the flow of urine.

  • Imaging of the bladder/kidneys
    You may have to get an ultrasound of the bladder and kidneys, which uses high-frequency ultrasound waves to create an image of your bladder/kidneys.

  • Cystoscopy
    If you have blood in the urine or abnormal ultrasound bladder results, you may be asked to undergo a flexible cystoscopy in the clinic. This is a day procedure that uses a fibre-optic telescope to inspect the bladder, urethra and prostate gland (in males).

  • Urodynamic Evaluation
    This is a real-time functional study of the bladder and the outlet and involves the infusion of saline into the bladder via a small urethral catheter. As the bladder fills and then empties, we will be able to assess its storage and voiding patterns to reach a diagnosis of the patient’s issues. The aim of this study is to replicate the patient’s problem so that we can give a more specific treatment plan.

Can an overactive bladder be treated?

An overactive bladder is a fairly common issue and can be treated with assistance from your urologist. The form of treatment depends on a variety of factors, such as what is causing your overactive bladder symptoms.

How is an overactive bladder treated?

1. Drug treatment

Medications may be required if self-management or lifestyle changes are inadequate to control the symptoms. Common medications are muscarinic receptor antagonists, Beta-3 agonists, desmopressin and local oestrogen.

2. Third-line treatment

Sometimes the medications prescribed do not improve the OAB symptoms. In such cases, other treatment options are available. Common treatment options for OAB symptoms are:

a. Neurotoxin bladder injections

b. Nerve stimulation, also known as neuromodulation

c. Surgery to increase bladder volume

3. Self-management 

OAB symptoms are often bothersome but not life-threatening. They can last for a long time and there is no fast cure. In most cases, self-management is offered as the first step of treatment. Your urologist will advise you on what treatment options would best suit your situation and how to actively manage your symptoms. Some self-management measures are: 

Fluid restriction after counselling

The use of absorbent pads/ adult diapers for severe leakage 

Bladder retraining

Pelvic floor exercises (also known as Kegel exercises)

Exercise and stress management

4. Lifestyle changes / Coping mechanisms

Your urologist may also recommend certain lifestyle changes to help manage your symptoms and improve your quality of life.

Drink less before and during long trips.

Drink less in the evening to avoid getting up at night to urinate.

Reduce/avoid alcohol and caffeinated drinks (eg, coffee, tea and cola) because these beverages increase urine production and irritate the bladder.

Avoid foods that can irritate the bladder and worsen OAB symptoms. Some examples of these are artificial sweeteners, spicy food, citrus fruits and juices, caffeine and soft drinks.

Maintain a healthy weight (your Body Mass Index should be between 18-25 kg/m2). Reducing your weight may lead to an improvement in incontinence.

Does drinking water help with an overactive bladder?

Drinking more water may exacerbate your overactive bladder symptoms. However, most patients tend to dehydrate themselves to avoid the issues but this is not encouraged. Long term dehydration does not help in training the bladder and is detrimental to the kidneys.


Although OAB symptoms are not life-threatening, they usually can greatly impair one’s quality of life. It is important not only to feel healthy but also to feel free from the psychological pressure of living with OAB symptoms. With the right combination of treatments and keeping your symptoms under control, it is possible to live a healthy and active life.

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Dr. Fiona Wu 2

Dr Fiona Wu
Consultant Urologist

MBBS (S'pore), MRCS (Edin), MMED (Surg),
MMED (Clinical Investigation),
FRCS (Urol) (RCPSG), FAMS (Urology)

Dr Fiona Wu is an experienced Consultant Urologist and is the Medical Director of Aare Urocare.

Prior to her private practice, she spent 15 years in public service. She was a Consultant in the Department of Urology at National University Hospital (NUH), Alexandra Hospital and Ng Teng Fong General Hospital.

She believes in treating urinary incontinence in a holistic way using minimally invasive methods – this ranges from laser treatment, neurotoxin injections, electromagnetic nerve stimulation to minimally invasive surgeries, etc. She worked closely with the gynaecology and colorectal departments to treat complex pelvic floor conditions and continues to do so in her own practice.

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