My baby is 5mo and lately he has getting up at night (after a month of getting into a napping routine). He just plays and then sleeps after a good 3-4 hours. What should I do?

Your baby is doing what every baby does -- eat, pee and play. I read an article in one of the US based site that most number of sleepless nights for person is when his/her baby is 2 to 5 months old. New born take time to get into day and night cycle by end of 7 month your baby will slowly fix a daily cycle and have normal day play and night sleep pattern. Good luck!