Not all of the causes of bedwetting are known. Children who wet the bed have difficulty waking up to go to the toilet when their bladder is full. Sometimes their bladder is smaller or ‘irritable’ and holds less urine.

Not waking to bladder signals
Hereditary factors
Anti-diuretic hormone
Poor daytime toilet habits
Bladder over-activity
Other reasons for bed-wetting

Not waking to bladder signals

Just as our children reach developmental milestones at different ages, learning to control their bladder during the night is yet another stage. Your child may have crawled, walked and talked just like his/her peers but for your child staying dry at night is taking longer to master. For some children the message that the bladder is full is not getting back to the brain and waking the child so they can go to the toilet. As a result the child has no conscious control over wetting their bed. Children need to develop voluntary bladder control even when asleep. A certain stage of physical maturity must be reached for this to take place and it happens at different times for different children.

Hereditary Factors

Bedwetting does tend to run in families. If one or both parents used to wet the bed when they were children, then it is quite likely to occur in their children.

Anti-Diuretic Hormone

Recent research has found that many children who wet the bed produce less of a hormone known as antidiuretic hormone (ADH) during sleep. This hormone normally reduces urine production during sleep. These children produce more urine during the hours of sleep than their bladders can hold. If they do not wake up, the bladder releases the urine and the child wets the bed.

In some rare cases, there may be a physical problem that is the cause of the child’s bed-wetting. For this reason, it is very important that a General Practitioner (GP) examines your child. The doctor will consider all the details and recommend the best treatment.

Poor Daytime Toilet Habits

Some research suggests that children who wet at night usually have poor daytime toilet habits. At first you may think your child does not have any daytime issues. However consider the following questions:

  • Does my child hold her/his urine then wiggle, dance or hold him/herself?
  • Are there times when my child has to go the toilet immediately?
  • Does my child still have accidents during the day?
  • Does my child need to go to the toilet frequently during the day?
  • Is it difficult to get my child to go to the toilet when they need to?
  • Does my child dribble before/after/between toilet trips?
  • Has my child had a urinary tract infection?
  • Does my child suffer from constipation problems?
  • Does my child rush when urinating and may therefore not completely empty his/her bladder?


Poor daytime toilet habits may be one of the most common causes for bedwetting. Some research points to daytime toilet habits as a major contributing factor to bedwetting. Studies have shown that children who wet during the day and those with constipation have a much higher incidence of bedwetting. Children who go often during the day (frequently) or go quickly (urgently) have also been shown to be more likely to wet at night.

Children who really need to urinate during the day can tighten their bottom muscles (sphincter), squat or wiggle, and run to the toilet in order to avoid having an accident. At night, these same children cannot do this since they are asleep and they cannot consciously clench their bottom muscles or run to the toilet. They can get away with holding during the day, but not at night. If a child does not take his time and get all the urine out when he goes to the toilet during the day, he will most likely not completely empty his bladder prior to going to bed. The urine left behind will cause the bladder to fill up more quickly, and while the child is sleeping, the bladder will be more likely to empty.

Tackling some of your child’s poor daytime toilet habits may result in more success during the night. Explain to your child why you wish to take the time to correct some of their daytime toilet habits. Remember that your child needs to ‘buy’ into the reasons in order for them to be motivated to change.

Bladder Over-activity

Some children have wetting problems in the day which can cause or have an effect on night time wetting. The most common problem is an overactive bladder; this occurs when the muscles in the bladder contract before it is full causing a need to go to the toilet urgently and frequently. The spasms caused by an overactive bladder can also occur in the night during sleep.

Indications of an overactive bladder are damp pants during the day and at night. There will often be variable size wet patches in the bed and the child will often wake up after wetting. An assessment of daytime wetting by a suitable health professional is always recommended as medicine and other treatments can be prescribed.

Other reasons for bedwetting may include:

  • Stress in the home or at school creating anxiety
  • Deep sleep & sleep disorders – your bedwetting child sleeps so deeply that he or she doesn’t wake up when the urge to urinate occurs
  • Bladder over activity
  • Spinal abnormalities
  • Urinary tract infection (UTI)
  • Small bladder size
  • Constipation – children with constipation problems are more likely to be bed-wetters
  • Birth defects and medical conditions (consult your Doctor if you suspect these factors)
  • Diet – an excess of carbonated, caffeinated drinks and stimulants (like chocolate) during the day