Most cases of bedwetting (enuresis) are caused by slower than normal development of the central nervous system, bladder muscles and bladder capacity. There may be a delay in the production of antidiuretic hormone, which reduces the amount of urine produced at night. However, normal childhood development covers a wide range and slower development does not mean that anything is wrong with the child. These children are still physically and emotionally healthy and normal and they will eventually have control over their bladders at night.

Secondary enuresis (bedwetting after a period of remaining dry at night) is typically the result of stress, fears or insecurities, such as the birth of a sibling, moving, the divorce of parents, a hospitalization, the death of a loved one or abuse. These factors can also prolong primary enuresis (bedwetting that has occurred since infancy).

According to the American Academy of Pediatrics, only around 1 percent of enuresis cases are related to diseases or other physical problems. Physical problems that can result in enuresis include:

• Urinary infections. Infections in the kidneys, bladder or elsewhere in the urinary tract can result in bedwetting. These are generally accompanied by cloudy or discolored urine and discomfort or pain during urination.
  
  
• Diabetes. Type 1 diabetes may lead to bedwetting. These children tend to urinate frequently during the day, as well. They may also lose weight despite having a healthy appetite.
  
  
• Physical defects or injuries. Abnormalities in the urinary tract and problems with the spinal cord can cause bedwetting.
  
  
• Sleep apnea. Temporary interruptions in breathing during sleep, generally due to an obstruction in the airways, can lead to wetting the bed. Other symptoms of this condition include snoring, frequent sinus or ear infections, sore throat and drowsiness during the day.

Bedwetting runs in families. Most children who have a problem with wetting their beds have a close relative who had a similar problem as a child. Typically, one or both parents wet their beds during childhood. Scientists have even located certain genes that influence bedwetting.

Other risk factors for enuresis include:

• Gender. Boys are more likely than girls to continue to wet their beds until an older age. This is because girls physically mature more quickly than boys.
  
  
• Sleep patterns. Many children who wet their beds are believed to be deep sleepers. They may sleep too deeply to be awakened by the need to urinate.
  
  
• Other conditions. Children with some conditions (e.g., attention deficit hyperactivity disorder [ADHD], learning disabilities, allergies) are more likely to wet the bed at an older age.