Reviewed November 2019

How weight gain can cause stress incontinence

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Incontinence means the ‘involuntary loss of urine’ and affects around 39.9% of women in the UK.1 There are many types of incontinence, but the two main types are referred to as ‘stress incontinence’ and ‘urge incontinence’. These two types of incontinence can be present together, where the condition is called ‘mixed urinary incontinence’.2

A normal bladder gradually expands as it fills with urine produced by the kidneys. The bladder wall is made of muscle which sits in a relaxed state, and the tube which empties the bladder, the urethra, is held closed by the muscles in the pelvis, which are known as the pelvic floor muscles.

A healthy person feels the need to pass urine when their bladder fills to around 200ml, although generally speaking a healthy bladder can hold up to around 500ml.3 The sensation of needing to pass urine occurs due to complex signals in the brain and spinal cord, which in turn cause the bladder muscle to contract and the muscles surrounding the urethra to relax.

An element of this is under voluntary control, which means that we can choose when we want to pass urine, and this is something we learn during early childhood. However, a number of things can occur to mean that these normal actions are overpowered, leading to urinary incontinence.

Stress incontinence occurs when the pressure in the abdomen increases and the bladder and pelvic floor muscles are unable to prevent the loss or urine. This can cause anything from small leaks to losses of large amounts of urine. If you have weakened pelvic floor muscles, stress incontinence can occur when you cough, sneeze, laugh, or exercise.

What does weight have to do with stress incontinence?

A high BMI is known to be a risk factor for developing stress incontinence, however it is not known exactly why this is the case. It is thought to be due to the increased stress placed on a person’s pelvic tissues and the stretching and weakening of muscles due to the increased weight.4 This constant stress on the muscles can cause them to weaken more quickly than in a person of ‘normal’ weight. Studies have shown that the risk of incontinence increases as BMI increases.5 Alongside a higher BMI, a larger waist circumference is also a risk factor for urinary incontinence.6

Obesity also causes an increase in the pressure in the abdomen, which can overpower the pressure created by the pelvic floor muscles around the urethra, causing leakage or incontinence. Obesity can also stretch the nerves around the area of the bladder and pelvis, which may cause them to be less responsive to the sensation of a full bladder, and less able to control the bladder.

How can I get rid of my incontinence issues?

Even losing a small amount of weight can sometimes produce huge improvements regarding your incontinence issues. Some studies have shown that losing just 5% of your body weight if you are overweight can halve the number of episodes of incontinence.7 However, it is extremely difficult to establish for definite whether an individual’s weight is causing their incontinence, and results from weight loss do vary hugely from person to person. Often, there are a number of factors involved and weight gain is not the only cause, although it very frequently plays a role.

Traditional methods to lose weight, such as through healthy dieting and exercise, are relatively non-invasive — certainly much less so than taking tablets or having surgery in an attempt to solve your incontinence problems. On top of this, the health benefits of being a healthy weight do not lie with getting rid of incontinence alone. For this reason, in an overweight woman with stress incontinence, healthy weight loss is often a good place to start.

Weight gain can occur for many reasons, and women who have suffered from stress incontinence for a long time often experience a worsening in their incontinence when they gain weight.

Could there be other causes of my stress incontinence?

There are many other causes of stress incontinence, but all generally involve weakening of the pelvic floor muscles. Causes of this include having a number of children by vaginal delivery, having complex vaginal deliveries or a large baby, having a previous hysterectomy, and ageing (all muscles weaken with age).8

New incontinence should always be discussed with a doctor, as it can be caused by a wide range of things. Sometimes it can occur temporarily due to urine infections, and sometimes it can be caused by more serious problems with the spinal cord. Once the easily reversible and the serious conditions have been ruled out, a plan for improving and managing incontinence can be formed.

Many women find it difficult to discuss urinary incontinence with their doctor, as it can be an embarrassing subject which is difficult to talk about. It’s important to remember that it is a common and often very treatable condition, and around 60% of women can significantly improve their urinary incontinence by doing pelvic floor exercises, with no other treatment necessary.9 However, if this doesn’t work, there are many other options available, from tablets to surgery, depending on the exact causes and severity of the problem. Urinary incontinence can hugely affect a woman’s quality of life, but don’t panic if it’s something that affects you — it is often easily improved.

Featured image is a photo of a bathroom, from the perspective of the door. A toilet is visible in the centre of the frame. The bathroom is entirely white

Last updated November 2019
Next update due 2020

Dr Evie Winther MBChB 

Evie is a GP registrar currently based in Yorkshire. She loves running, cycling, and going to the gym, and is passionate about encouraging involvement and equal opportunities for women in sport. She believes it is hugely important for women to have honest information about their health freely available and be able to ask questions without fear of judgement.

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  1. NICE, ‘Incontinence – urinary, in women’, Clinical Knowledge Summary, National Institute for Health and Care Excellence, October 2019 [online]!backgroundSub:2 (accessed 24 November 2019)
  2. DeMaagd, G.A., et al., Management of urinary incontinence, Pharmacy and Therapeutics, Vol. 37, No. 6, 2012, pp.345-361, 361B-361H.
  3. NHS, Bladder training, Patient information, Department of Urology, Brighton and Sussex University Hospitals, February 2019 [online] (accessed 24 November 2019)
  4. NICE, ‘Incontinence – urinary, in women’, Clinical Knowledge Summary, National Institute for Health and Care Excellence, October 2019 [online]!backgroundSubSub (accessed 24 November 2019)
  5. Subak, L., et al., Obesity and Urinary Incontinence: Epidemiology and Clinical Research Update, J Urol, Vol. 182, Suppl. 6, 2009, pp. S2-S7.
  6. Phelan, S., et al., ‘Prevalence and Risk Factors for Urinary Incontinence in Overweight and Obese Diabetic Women, Action for Health in Diabetes (Look AHEAD) study’, Diabetes Care, Vol. 32, No. 8, 2009, pp. 1391-1397.
  7. Subak, L., et al., Obesity and Urinary Incontinence: Epidemiology and Clinical Research Update, J Urol, Vol. 182, Suppl. 6, 2009, pp. S2-S7.
  8. NICE, ‘Incontinence – urinary, in women’, Clinical Knowledge Summary, National Institute for Health and Care Excellence, October 2019 [online]!backgroundSub:1 (accessed 24 November 2019)
  9. Laggro-Janssen, T.L., et al., Controlled trial of pelvic floor exercises in the treatment of urinary stress incontinence in general practice, BR J Gen Pract, Vol. 41, No. 352, 1991, pp. 445-449.

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