Bedwetting (Nocturnal Enuresis)

How common bedwetting is at each age

Night-time bladder control is the last stage of toilet training and develops at very different ages. Doctors generally do not diagnose enuresis before age 5.

Each year about 15% of children who wet the bed become dry without treatment. Boys are affected about twice as often as girls.

Types of bedwetting

• Primary enuresis: the child has never been dry at night for 6 months. This is the most common type and is usually developmental.
• Secondary enuresis: wetting starts again after at least 6 months of dryness. This suggests a trigger such as an infection, constipation, diabetes or emotional stress.
• Monosymptomatic: only night-time wetting.
• Non-monosymptomatic: night wetting with daytime symptoms such as urgency, frequency or accidents. This needs more investigation.

Causes of bedwetting

Common causes in children

• Making too much urine at night: many children do not produce enough of the hormone vasopressin, which normally reduces urine output overnight.
• Small or overactive bladder: the bladder empties before morning.
• Not waking to a full bladder: the child sleeps through the signal.
• Family history: if one parent wet the bed, a child has a much higher chance.
• Constipation: a full rectum presses on the bladder and is a commonly missed cause.

Causes to consider in sudden or secondary bedwetting

• Urinary tract infection
• Type 1 diabetes: new bedwetting with thirst and weight loss
• Sleep apnea from large tonsils or adenoids
• Stress: a new sibling, starting school, moving, bullying or family conflict
• ADHD, which is linked with bedwetting

Adult bedwetting

Bedwetting in adults is less common and always deserves a medical review. Causes include an overactive bladder, an enlarged prostate, urinary retention with overflow, sleep apnea, diabetes, heart failure, nerve problems, alcohol, sedative medicines and diuretics taken late in the day.

How doctors assess bedwetting

Expect questions about how often it happens, daytime symptoms, bowel habits, drinking patterns, snoring and family history. A bladder diary over a few days records drinks, voids and wet nights. A doctor will usually:

• examine the belly, back and genitals
• test the urine for glucose and infection
• consider an ultrasound or bladder scan if daytime symptoms or an abnormal stream suggest a structural problem

Treatment

Treatment is usually not needed before age 6 or 7, unless the child is distressed.

Practical steps

• Drink evenly through the day, with less in the last hour or two before bed.
• Avoid caffeine and fizzy drinks, especially in the evening.
• Pass urine before bed and use the toilet regularly in the day.
• Treat constipation.
• Use protective pants or bed pads for comfort. Do not punish wet nights, which makes it worse.

Bed alarms

A moisture sensor triggers an alarm at the first drops of urine, teaching the child to wake. Alarms are the most effective long-term treatment, with lower relapse rates than medicine. They typically need 6 to 16 weeks of nightly use and a parent's help with waking.

Medicines

• Desmopressin: a synthetic version of vasopressin that reduces night-time urine. It works quickly and is useful for sleepovers and camps. Fluids must be limited in the evening while taking it, because of a risk of low blood sodium.
• Bladder-relaxing medicines may help when there are daytime symptoms of overactive bladder.

Frequently asked questions

At what age is bedwetting a problem?

Bedwetting is not considered a problem before age 5, and many doctors wait until 6 or 7 to treat it. It deserves attention at any age if it starts suddenly after a dry period, comes with daytime symptoms, or upsets the child.

What causes sudden bedwetting in a child who was dry?

Common causes include a urinary tract infection, constipation, emotional stress and, less often, type 1 diabetes. A urine test checks for infection and sugar. Any child with new bedwetting plus extreme thirst, weight loss or tiredness should be seen the same day.

Do bedwetting alarms work?

Yes. Bed alarms help about two-thirds of children who use them consistently for several months, and they have lower relapse rates than medicines. They work best in motivated children aged 7 and over, with a parent helping them wake when the alarm goes off.

Is bedwetting genetic?

Yes, it often runs in families. If one parent wet the bed as a child, the chance is roughly 40%, and if both did, it rises to around 70%. Children usually become dry at a similar age to their parent.

Is adult bedwetting a sign of something serious?

It can be. Adult bedwetting may be caused by an overactive bladder, prostate enlargement, urinary retention, sleep apnea, diabetes or nerve problems. It is not normal, so see a doctor for an assessment.