No, not always. The development of your baby's central nervous system—in other words, his brain—is more important than his height or weight. Every baby's sleeping habits are unique. Some babies need more time in bed, while others can fall asleep quickly if they're left alone so they can get the rest they need. The short answer is that you cannot estimate how much sleep a baby will need by looking at her size. Each child has an individual sleep pattern that changes over time. But there are some factors that may indicate whether your baby is getting enough sleep, including her weight and rate of growth. As she gets older, your growing girl will need more sleep. On average, infants need 14 hours each day to grow properly. This number drops to 12 hours for children between 1 and 2 years old and 10 hours for those aged two and up. Even though they seem little, babies and toddlers actually spend nearly half of their time sleeping! In addition to age, weight is used by doctors to determine whether your baby is getting enough sleep. If she is under 11 pounds, she is considered small for her age. If she is under 5 pounds, she is very small for her age. Sleep studies have shown that young children who are overweight tend to wake up more often during the night and experience less deep sleep.