Nightwaking has developmental benefits. Sleep researchers believe that babies sleep "smarter" than adults do. They theorize that light sleep helps the brain develop because the brain doesn't rest during REM sleep. In fact, blood flow to the brain nearly doubles during REM sleep.Yup, Jack too. :) He wakes every hour...!
During REM sleep the body increases its manufacture of certain nerve proteins, the building blocks of the brain. Learning is also thought to occur during the active stage of sleep. The brain may use this time to process information acquired while awake, storing what is beneficial to the individual and discarding what is not. Some sleep researchers believe that REM sleeps acts to auto-stimulate the developing brain, providing beneficial imagery that promotes mental development.
One day as I was explaining the theory that light sleep helps babies' brains develop, a tired mother of a wakeful infant chuckled and said, "If that's true, my baby's going to be very smart."
Oh and the sleeping through the night part? 1-4 months is right. They begin night-waking after that.
Meanwhile, Jack is teething and has been waking up rolling over onto his tummy, and even sitting up once. So I reckon the wakings is likely due to both teething and his developmental milestones.
Yet, even though babies achieve this sleep maturity some time during the last half of the first year, many still wake up. The reason? Painful stimuli, such as colds and teething pain, become more frequent. Major developmental milestones, such as sitting, crawling, and walking, drive babies to "practice" their new developmental skills in their sleep.