Most of the babies pass urine in the first 24 hours of life. Many of them pass urine during delivery itself and if so, they may not pass urine during the initial hours. Try to feed frequently; it may encourage him to pass urine early.

If the baby is a boy, and if he is not passing urine, request the pediatrician to consider what is called posterior urethral valve; which is a partial block of the tube which carries the urine from the bladder through the penis. If picked up early, this condition can be rectified with medical management.