What's the maximum number of hours a baby should sleep?
For night sleep, the longest stretch should NOT exceed age in weeks +1, with a maximum of 12 to 12.5 hours. Our goal is to have good awake time during the day for brain development and get those needed calories in during the day as well.
This means we do not want time from bedtime (when you place baby down in the crib/bassinet at night) until morning time (when your baby comes out into the light for daytime) to exceed 12 to 12.5 hours. So, yes, if your baby is still asleep at 12.5 hours after bedtime, please wake that sweet darling.
For example, if a baby is 6 weeks of age, please wake her if it has been longer than 7 hours since the start of the last feeding during the night.
Another example, if your 5 month old went into the crib at 7:00pm, please wake him by 7:30am.
If your baby is under 4 weeks or not gaining weight please follow the advice of your pediatrician. Most will say not to exceed 3 to 4 hours during the night.