Doctors aren’t always sure what causes bedwetting in older kids. But they do know that the brain and bladder aren’t communicating well. In babies, the connections between the bladder and the brain aren’t fully formed, so the bladder releases urine whenever it feels full. As kids get older, the nerve connections between the bladder and brain form, and they gain control over when they urinate. They develop daytime control first. It takes some kids much longer to develop nighttime control. Again, doctors don’t always know why. Some kids’ kidneys may make more urine at night, or their brains simply don’t get the message to wake up to urinate.