Bedwetting is a common childhood condition affecting about half a million children and young people in the UK. One in 15 seven year olds and 1 in 75 teenagers have night-time accidents. Boys are twice as likely to suffer as girls and the risk is 44% if one parent wet the bed and 77% if both did, suggesting a genetic link.

The causes of bedwetting

There are three main reasons why children wet the bed:

1. Their bladders don't stretch enough to hold all the wee they make at night

The cause of this could be constipation - a bowel full of poo pushes on a child's bladder limiting the space it has to stretch and fill causing day and night time accidents. An assessment by a doctor and laxative treatment is usually needed to sort out childhood constipation.

A child's bladder may be 'overactive' and give an urgent signal to empty before it's full. An overactive bladder usually holds lower than average amounts of wee. Signs of this are if a child is weeing over 7 times a day, they can't hold on even for short amounts of time or gets 'caught short' with very little warning.

Any underlying constipation daytime wetting issues should always be treated first as a priority over the night time. There is medication which can be prescribed for bladder over activity for children over five years.

Keeping a child's bladder healthy is also really important and it's a good idea to check how much a child who wets the bed is drinking and when. Children need around 6 - 8 drinks of water based fluid spread throughout the day and to stop drinking an hour or so before bed. Caffeinated or fizzy drinks particularly close to bedtime can irritate a child's bladder and make it more likely that they will be wet.

2. They produce too much wee at night

The hormone vasopressin tells the kidneys to make less wee at night. If a child doesn't produce enough vasopressin while they're asleep, they keep making daytime volumes of wee which their bladder can't hold.

3. They don't wake up when their bladder sends a signal that it's full

Some children just don't wake up when their bladder tries to tell them it's full or they wake just afterwards when it's too late. This isn't related to their depth of sleep but is connected to their ability to rouse from sleep to the full bladder signal.

Night time accidents can be caused by one or more of these reasons but they are all treatable.

Bedwetting is an issue which is commonly misunderstood and not always talked about as openly as it should be. Many parents mistakenly take a 'watch and wait' approach thinking that the wetting will eventually get better, but for children who have always been wet and never or rarely have a dry night it is important that they are seen by a health professional.  The vast majority of children do eventually grow out of bedwetting, but this isn't a reason to delay getting help.

Parents delay seeking help from a health care professional because:

• They think their child is being lazy or it's their fault in some way
• They're too embarrassed to admit their child has a problem
• They've been told that their child will grow out of it so they decide to 'watch and wait.'