Is it ok for my newborn to go 4hrs witjout eating if she is sleeping. She is 3 weeks. She eats well but sometimes is just not ready. Do I wake her?

Let sleep if night. During the night, it is fine to let a 3wk old sleep up to 8hrs. They have more than 12hrs worth of food being processed in their intestines & as long as baby is wetting diapers & growing this is a great schedule. During the day, i would always wake a 3wk old after 2hrs to feed so you can get more day feeds in to protect that long night sleep period.A 4hr day nap will mess up your nights.