Nocturnal enuresis
Bedwetting is not your child's fault and there's often no obvious reason why it happens. In many cases, the problem runs in families.
Most experts believe there may be more than one underlying cause.
The bladder is a balloon-like organ in the pelvis that stores urine. When it's full, urine flows out of it through a tube called the urethra, found in the centre of the penis in boys and just above the main opening of the vagina in girls.
Some children affected by bedwetting have 'overactive bladder syndrome'. This is where the muscles that control the bladder go into spasm, leading to the involuntary leaking of urine.
Drinking lots of fluids during the evening could cause your child to wet the bed during the night, particularly if they have a small bladder capacity. Drinks containing caffeine, such as cola, tea, and coffee, can also stimulate an increase in the production of urine.
In some cases of bedwetting, the childs body doesn't produce enough of a hormone called vasopressin, which regulates urine production. This means their kidneys produce too much urine for their bladder to cope with.
Once the amount of urine in the bladder reaches a certain point, most people wake up as they feel the need to go to the toilet. However, some younger children are particularly deep sleepers, and their brain doesn't respond to signals sent to the brain from their bladder, so they don't wake up.
Alternatively, in some children the nerves attached to the bladder may not yet be fully developed, so they don't generate a strong enough signal to send to the brain.
Sometimes, a child may wake up during the night with a full bladder but not go to the toilet. This may be because of childhood fears, such as being scared of the dark.
Bedwetting can also be caused by an underlying health condition, such as:
In some cases, bedwetting can be a sign that your child is upset or worried. Starting a new school, being bullied, or the arrival of a new baby in the family can be very stressful for a young child.
If your child has started wetting the bed after previously being dry for a period of six months or more (known as secondary nocturnal enuresis), emotional problems such as stress and anxiety may be responsible.
Bedwetting can be worrying and frustrating, but it's common for children to accidentally wet the bed during the night. The problem usually resolves in time.
Bedwetting is usually only regarded as a medical issue when it occurs in children who are five years old or older and who wet the bed at least twice a week.
Bedwetting is not your child's fault and there's often no obvious reason why it happens. In many cases, the problem runs in families.
It's likely your GP will ask you or your child about their bedwetting in order to check for any underlying cause and help determine the most effective treatment.
Although most children will stop wetting the bed as they get older, there are a number of treatments that can be tried.