not neccessarily. I breastfed, so I could never tell how much my lo was taking in, but for growth spurts, he still woke at night. I don't think their tummies can hold so much milk at one feeding, so they space them out. what makes me think that she's hungry, is that she will wake an hour or two after you put her back to sleep, as if saying, "Mom, I'm really hungry"! Then she sleeps until morning. When she takes her first bottle in the morning, does she act starving?