Wet sheets, wet pajamas, an embarrassed child and frustrated parents: This scene is familiar to many of us. Bed-wetting, also known as nocturnal enuresis, often is a normal part of a child’s development. Most children are fully toilet-trained and dry at night by the age of 4, but 15 percent of 5-year-olds entering kindergarten still wet the bed. Twice as many boys as girls wet the bed at night after the age of 6; and by the age of 8, fewer than 5 percent of children wet the bed.

Several factors are thought to cause bed-wetting. Some children have a small or poorly- developed bladder. Often, a bed-wetter simply can’t recognize when his bladder is full, especially if he is a particularly sound sleeper. Stress—such as a new sibling or the death or illness in the family—may trigger bed-wetting in a child. A child has an 80 percent chance of being a bed-wetter if both parents wet the bed, as well. Bed-wetting is more common in children with untreated ADD/ADHD.

Rare but serious conditions can be associated with bed-wetting. Children who have been dry at night for a long time and develop enuresis should be evaluated for an underlying condition, such as juvenile diabetes, obstructive sleep apnea, urinary tract infection, constipation or hormone imbalances.

Some children with chronic constipation will have a diminished bladder capacity and wet the bed. You should see your child’s doctor if your child still wets the bed after the age of 6 and is not improving, he or she begins to wet the bed after a long period of dryness, has fever, painful urination or other symptoms associated with the bed-wetting, or your child snores or is constipated.

What can be done about a child who does not have an underlying medical problem, which is the case with most bedwetters? First, be patient. Your child is not purposefully wetting the bed. Do not get angry and do not punish your child. Try the following:

> Limit fluids before bedtime unless your child is hot or involved in sports in the evening. Give your child about 20 percent of his/her daily fluids after 5 p.m.

> Allow your child no caffeinated drinks after late afternoon, if ever.

> Have your child void at bedtime.

> Encourage regular toilet use during the day.

> Avoid constipation with a diet appropriate in fruit and fiber.

See the doctor if none of these remedies help, or if your child is consistently wetting the bed after the age of 6 or your child has other symptoms. Expect your child’s doctor to perform a physical exam and take a thorough history about daytime urine habits, any stresses in life, associated symptoms and family history. A urinalysis may be needed. In some cases, X-ray imaging may be ordered. Treatments prescribed by your doctor may include:

> Moisture alarms sense when your child first begins to void at night, and wake your child. These alarms take time to work (6 to 12 weeks) but are highly effective.

> As a last resort, medications may be prescribed, such as hormones and antidepressants. However, these may have side effects. Many physicians prescribe these only in children about age 10 who may experience social stigma from enuresis.

> Alternative therapies such as acupuncture, hypnosis and homeopathic remedies have been tried, but no evidence shows they are effective.

Remember that bed-wetting is a developmental issue in many children—a nuisance that is almost always outgrown.

Dr. Joseph Kahn is president of Mercy Children’s Hospital Services, mercy.net.