You asked

What causes bed-wetting?

Bed-wetting: the basics
Bed-wetting is a problem that is quite common for many school age children. However, they will grow out of it and for the persistent bed-wetters the problem can be treated easily.
Most children stop wetting during the day by the time they are about three years old and wetting the bed by the time they are five, although most preschoolers still wet the bed from time to time.
At the age of four, almost 1 in 3 children wet, this figure reduces to 1 in 10 by age six and 1 in 20 by age ten.
What causes bed-wetting?
Bed-wetting is not caused by a child being too lazy to get out of bed or as a bid to get attention. It is something that your child cannot control. Bed-wetting often runs in the family, so if you or your partner wet the bed as a child, then you may find that your child is similarly inclined.
What happens?
Bed-wetting happens when your child fails to wake from sleep despite a full bladder. At a certain point the bladder will then empty.
Bed-wetters are often heavy sleepers who are difficult to rouse from sleep.
Due to the low level of a hormone that controls urine output overnight, some children produce more urine at night than is normal.
Some bed-wetters have small bladders that cannot hold a large volume of urine overnight without having to be emptied.
The Brain:
  • Tells the kidneys to produce less urine at night
  • Tells the bladder when to empty
The Kidneys:
  • Help clean the blood
  • Rid the body of urine
The Bladder:
  • Holds the urine until such time it can be gotten rid of
  • Signals the brain when the bladder is full
  • May empty by itself if the brain doesn't wake up your child at night

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