It seems my 6 wk old could sleep 8 hrs if i let her but i wake her to feed her after 6 hrs. how long can i let her sleep before i need to feed her?

Until breakfast: A baby over 1 month old, who is happy, normal, and growing well, can eat whenever he wants to. Most babies do not sleep through the night at that age, but a few do. Parents of those few babies can feel lucky that they don't have to get up at night. Usually, a bedtime feeding at 10 P.M. Is fine. Then, the baby can be woken up at 5-6 A.M. To eat, to best match the parents' breakfast schedule.

Let her sleep: As long as she is eating when she is awake and wetting and filling diapers. Let her sleep. She will wake when she's hungry. Get some sleep yourself.

Let Sleep: I never wake a healthy baby for feedings. If you are fortunate enough for them to sleep an extended period of time and they are both healthy and gaining weight, enjoy. Let nature take its' course.

A Full Night: You have asked this question several times in different ways. The answers are all the same. Let her sleep!

Let baby set schedul: Any 6 wk old that has been feeding & growing well can be left alone to sleep as long as 8 or more hours. Their intestines has food they are continuing to digest & use during this period & if baby can deal with it & thrive there is no reason to wake her.Babies don't sleep more than 4 hr without cycling to a lighter sleep state so the fact that yours can settle back & sleep longer is wonderful.