Most babies will be feeding in 2.5-3 hour intervals at this age. At night your baby will begin to extend to one longer stretch of sleep without a feeding that will be up to 4-6 hours. After this long stretch they will wake in a regular feeding pattern (every 2-4) for a feed the rest of the night. If it has been 3 hours since your baby’s last feeding then it is likely they will need to be fed especially if it is after their longer stretch.
Your baby will also have a growth spurt around the sixteen week mark. During this growth spurt your baby will want to feed more frequently and you will need to follow their lead. This usually lasts a few days then feeding intervals will begin to resume in a regular feeding pattern again. If your baby’s sleep or feeding patterns change and it is around this time frame – it may signal your baby is going through a growth spurt and indeed will need to feed during night wakings.