Toilet training a child takes a lot of patience, time and understanding. Most children do not become fully toilet trained until they are between 2 and 4 years of age. Some will be able to stay dry during the day. Others may not be able to stay dry during the night until they are older. Nighttime bed-wetting, called enuresis, is normal and very common among preschoolers. It affects about 40 percent of 3-year-olds.

All of the causes of bed-wetting are not fully understood, but the following are the main reasons a child wets the bed:

• His bladder is not yet developed enough to hold urine for a full night, or
• He is not yet able to recognize when his bladder is full, wake up and use the toilet

Often, a child who has been dry at night will suddenly start bed-wetting again. When this happens it is usually due to stress in the child's life. Such stress could be due to a big change, such as a new baby in the home, moving, or a divorce. Children who are being physically or sexually abused may also develop enuresis. If your child wets the bed after having been dry at night in the past, your pediatrician should do an evaluation. The bed-wetting may be a sign that stress or a disease is causing the problem.

In trying to find the cause of your child's bed-wetting, your pediatrician may ask you the following questions:

• Is there a family history of bed-wetting?
• How often does your child urinate, and at what times of the day?
• When does your child wet the bed? Is she very active, upset or under unusual stress when it happens?
• Does your child tend to wet the bed after drinking carbonated beverages, caffeine, citrus juices or a lot of water?
• Is there anything unusual about how your child urinates or the way his urine looks?

If your pediatrician suspects a problem, he may take a urine sample from your child to check for signs of an infection or other problem. Your pediatrician may also order tests, such as X-ray films of the kidneys or bladder, if there are signs that wetting is due to more than just delayed development of bladder control.

If the tests point to a problem that may require surgery, your pediatrician may recommend that you see a pediatric urologist who is specially trained to treat children's urinary problems that require surgery.

Some parents fear that their child's bed-wetting is due to a disease or other physical problem. Actually, only about 1 percent of bed-wetting cases are related to diseases or defects such as:

• Bladder or kidney infections
• Diabetes
• Defects in the child's urinary system

With any of these cases, there will often be changes in how much and how often your child urinates during the day. Your child may also have discomfort while urinating. Tell your pediatrician if you see any of the following signs at any age:

• Unusual straining during urination, a very small or narrow stream of urine, or dribbling that is constant or happens just after urination
• Cloudy or pink urine, or bloodstains on underpants or nightclothes
• Daytime as well as nighttime wetting
• Burning during urination

Most school-age children who wet their beds have primary enuresis. This means they have never developed nighttime bladder control. Instead, they have had this condition since birth and often have a family history of the problem. Children who are older when they develop nighttime bladder control often have at least one parent who had the same problem. In most cases, these children become dry at about the same age that their parent(s) did.

Tips for Managing Bed-Wetting

A small number of children who wet the bed do not respond to any treatment. Fortunately, as each year passes, bed-wetting will decrease as the child's body matures. By the teen years almost all children will have out-grown the problem. Only one in 100 adults is troubled by persistent bed-wetting.

Until your older child outgrows bed-wetting, it is important that you give him support and encouragement. Be sensitive to your child's feelings about bed-wetting. For instance, children may not want to spend the night at a friend's house or go to summer camp. They may be embarrassed or scared that their friends will find out they wet the bed.

Make sure your child understands that bed-wetting is not his fault and that it will get better in time. Do not pressure your child to develop nighttime bladder control before her body is ready to do so. As hard as your child might try, the bed-wetting is beyond her control, and she may only get frustrated or depressed because she can not stop it.

Set a no teasing rule in your family. Do not let family members, especially siblings, tease a child who wets the bed. Explain to them that their brother or sister does not wet the bed on purpose. Do not make an issue of the bed-wetting every time it occurs.

If your child has enuresis, discussing it with your pediatrician can help you to understand it better. Your pediatrician can also reassure you that your child is normal and that he will eventually outgrow bed-wetting.

Until that happens naturally, however, the following steps might help the situation.

Take steps before bedtime.
Have your child use the toilet and avoid drinking large amounts of fluid just before bedtime.

Use a bed-wetting alarm device.
If your child reaches the age of 7 or 8 and is still not able to stay dry during the night, an alarm device might help. When the device senses urine, it sets off an alarm so that the child can wake up to use the toilet. Use this device exactly as directed so that it will detect the wetness right away and sound the alarm. Be sure your child resets the alarm before going back to sleep.

These alarms are available at most pharmacies and cost about $50. Although they provide a 60 percent to 90 percent cure rate, children often relapse once they stop using them. Alarms tend to be most helpful when children are starting to have some dry nights and already have some bladder control on their own.

Protect and change the bed.
Until your child can stay dry during the night, put a rubber or plastic cover between the sheet and mattress. This protects the bed from getting wet and smelling like urine.

Let your child help.
Encourage her to change the wet sheets and covers. This teaches responsibility. At the same time it can relieve your child of any embarrassment from having family members know every time she wets the bed. If others in the family do not have similar chores, though, your child may see this as punishment. In that case, it is not recommended.

Other treatments.
Some pediatricians recommend bladder stretching exercises. With these, your child gradually increases the time between daytime urinations so that the bladder can slowly stretch to hold more urine. Should you and your child decide together to try bladder-stretching exercises, follow instructions from your pediatrician.

When no other form of treatment works, your pediatrician may prescribe medication. The use of medications to treat bed-wetting is in dispute. Since primary enuresis stops as a child matures, some pediatricians worry that using medication may have more risks than benefits. Not only can medications cause side effects, but they may not work.

Your pediatrician can talk with you about the different medications that are available, their possible side effects, and their success rates.