What Is Nocturnal Enuresis (Bedwetting)?

When children urinate without control while they sleep, it is called nocturnal enuresis. It's also known as bedwetting.
Most children can control their bladder during the day and night by the age of 4. About 10% of children age 6 or 7 still can't stay dry, as they have day or nighttime "accidents." If a child experiences bladder control problems during sleep after the age of 7, it's worth looking into. Your health care provider can help.
Nocturnal enuresis is common for more than 5 million children in the U.S. It is slightly more common in boys than girls. This issue can be frustrating for children, parents and health care providers. As children spend more nights away from home (at camps, sleepovers and field trips), it is more imperative tolook for solutions. With patience and tools for treatment, most children will stop bedwetting.
There are two types of nocturnal enuresis. The testing, care and treatment for both types are very similar:
  • Primary nocturnal enuresis describes children who never achieved dry nights since potty training (typically these children have no accidents during the day time)
  • Secondary nocturnal enuresis is when a child achieved consistent dry nights for at least six months but has now started bedwetting again. Mostly, this type of bedwetting is related to a stressful event (e.g. birth of a sibling, parent divorce, etc.). Eating disorders and some medicines can cause secondary bedwetting.
 Contact your pediatrician if your child is experiencing either of these types of nocturnal enuresis.

How Does the Urinary System Work?

Urine is liquid waste from your body. Urine forms when the kidneys clean your blood. The "urinary tract" includes the organs in your body that make, store and remove urine.
Normally, the kidneys make about 1½ to 2 quarts of urine each day in an adult; less in children. Urine travels from the kidneys to the bladder through the ureters (the tubes that join them). The bladder has the job of storing and releasing urine. The muscular neck of the bladder stays closed in order to store urine. The urethra is the tube that carries urine from the bladder, out of the body. This area is kept closed with sphincter muscles.
The brain works with the bladder to control when to release urine. Once you are ready to release urine (i.e.: in a toilet), the brain sends a signal to the bladder. Then the bladder muscles contract. This pushes urine out of the bladder, through the urethra. The sphincter muscles open, and urine is released out of the body.
At first, infants release urine in an uncontrolled way by a simple reflex. As infants grow, several things develop to allow them to gain control over the way their bladder empties:
  • The bladder grows to hold more urine volume with age. 
  • By age 2-3 years, the child gains control over the sphincter and pelvic floor muscles. When they squeeze these muscles, children can hold the flow of urine until they reach to a toilet. 
  • The brain matures with age to allow children to relax or squeeze these muscles at all times. This is when they become "toilet trained." 
  • By age 7, 90% of children can control their bladder both day and night. If they have to use the bathroom at night, they will wake up and go.


Being lazy or willful is almost never a reason for a child's loss of bladder control. In a small number of cases, behavior may play a role. No matter the causes, parents need to be patient and supportive. Bedwetting is caused by a combination of things:

Family history (genetics)

Bedwetting can be inherited. The "bedwetting gene" is strong among families. Half of all children who have this problem had a parent who also struggled with bedwetting. This percent increases to 75% if both parents had enuresis. Close relatives (aunts, uncles and grandparents) may also share this gene, though you may not know it. A child without a family connection has only a 15% chance of bedwetting.

Slow development of brain-bladder control

Children who wet their beds are often described as "deep sleepers." Deep sleep affects the way the bladder communicates with the brain. Instead of waking up to use the toilet, the child's pelvic floor muscles relax and empty while the child sleeps. This brain-bladder control will develop naturally over time, or speed up with treatment.
Smaller than expected bladder capacity
Some children who have enuresis have bladders that can only hold a small amount of urine. This condition does not allow the child to sleep through the night without wetting the bed.

Making too much urine while asleep

Your child's kidneys may make too much urine at night, and the bladder may not be able to hold it all. Normally, the brain produces a hormone called "antidiuretic hormone (ADH)" which slows the kidney's urine production. It helps make less urine at night. When the brain does not make enough ADH or when the kidney stops responding to it, more urine is produced. The child will either have to wake up several times during the night to urinate or wet the bed. Caffeinated and carbonated drinks may also cause the kidneys to produce more urine. .
Type 1 diabetes (insulin dependent diabetes mellitus or "sugar diabetes") is caused by a lack of the hormone insulin. This hormone helps manage the sugar we get through food and drink. In untreated patients with type 1 diabetes, sugar is lost in the urine. This leads to a great loss of water. Some children with type 1 diabetes may have bedwetting as a symptom at the start of their illness.]

Sleep disorders

Some children have sleep disorders such as sleepwalking or obstructive sleep apnea (OSA). With OSA, less oxygen from poor breathing will cause the heart to produce "atrial natriuretic peptide (ANP)." This substance will cause the kidneys to produce extra urine at night.


The rectum lies behind the bladder. If constipation causes stool to store in the rectum, it will push on the bladder. This limits the way the bladder can hold urine, causing leaks.


Any form of stress can lead to bedwetting problems. If the stress from bedwetting itself affects your child or your family, it can make things worse. Children who wet the bed often fear being discovered and teased by their friends or siblings. Emotionally, a child can become withdrawn and nervous. Children with learning disorders or attention problems generally feel more stressed. These children commonly have bedwetting issues. Be aware of social stresses that can affect bedwetting, such as:
  • A new brother or sister
  • Sleeping alone
  • Starting a new school
  • A family crisis
  • An accident or trauma
Read the full article: Urology Care Foundation

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