In a lot of cases, there is no obvious cause for bedwetting but it often runs in the family.

Although there is no definite cause, it has been suggested that bedwetting may be linked to problems with messages between the bladder and the brain. Children have to learn how to recognize the feeling that they need to go to the toilet. Some children might simply have a small, or weak bladder, but this can usually be trained. Wetting the bed can also happen because the child is sleeping too deeply to wake up when they need the toilet.

Bedwetting is sometimes a sign that the child is upset about something. It may be linked to an issue such as starting a new school, a new baby in the family, moving house, or being bullied. Encourage your child to talk to you or another adult that they trust, such as a teacher, if they are worried about anything.

Bedwetting has been linked to not being able to breathe properly while asleep due to, for example, blocked sinuses. It has also been linked to a lack of the hormone ADH, which controls the production of urine. Bedwetting may be linked to diabetes, a urinary tract infection or constipation (which can irritate the bladder). These are all fairly rare causes of bedwetting. Your doctor will be able to advise you.