A new study finds 2 percent of teens wet the bed. While the problem becomes less frequent with age, those with severe cases are more likely to experience it as adults.
Half of 19-year-olds who wet the bed do so every night.
"Our findings challenge the myth that bedwetting will always get better and disappear as the child gets older," said study leader Chung Yeung from the Chinese University of Hong Kong.
Researchers at the Prince of Wales Hospital in the UK participated in the research, which is reported in the May issue of the urology journal BJUI International.
The 16,500 survey respondents ranged in age from five to 19.
"Bed wetting showed a general reduction as children got older," Yeung said. "However, this reduction was much greater in those with mild symptoms who wet the bed three or less times a week, compared to those with severe problems who were wetting the bed every night.
Yeung said the findings suggest parents of adolescents who wet the bed should seek medical help. "If these individuals are left untreated, the evidence suggests that they will continue to experience ongoing problems when they become adults."
Causes and solutions
Bed-wetting can be genetic or be related to hormonal deficiencies, infections or physical abnormalities. Around 15 percent of five year-olds wet the bed, previous research has shown and the new study confirms. Boys suffer the problem more than girls. By age 12, some 3 percent of children are still bed-wetters.
Bed-wetting—called nocturnal enuresis—isn't caused by drinking too much liquid before bedtime, according to the American Academy of Family Physicians. "It's not a psychological problem. It's not because the child is too lazy to get out of bed to go to the bathroom. And children do not wet the bed on purpose, out of spite or to irritate their parents."
Some doctors recommend therapies such as setting alarms during the night, bladder training and medications.
Live Science newsletter
Stay up to date on the latest science news by signing up for our Essentials newsletter.