Any ideas what might be the cause of frequent weeing in a 4 year old? I've taken him to the GP twice to have his urine tested and they say there's nothing wrong with him, but it's driving me mad and especially seems to happen after bedtime, he gets really distressed if I won't let him go, but it goes on for hours and he ends up falling asleep at about 9, 10pm.
He can happily go for hours during the day when distracted by interesting things without weeing, and if I can get him to go to sleep then he's dry in the night for 12 hours or more, and has been since he was about 2 - well before he was potty trained in the day!