newborns should generally be given a feed every 2 hours. a newborn baby is still too young to do on demand feeding, and even if he or she is hungry, he may not always wake up to ask for a feed.
so, it is important you wake up your baby every 2 hours and feed him, till the time he gains the perfect weight and is at least 2 months old, by when he will know how to ask for a feed when he needs it.
https://www.breastfeedingbasics.com/articles/waking-a-sleepy-baby
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