Analyzing surveys from 230 first-time mothers at Penn State, Dr. Ian Paul, a pediatrician, found that babies slept for longer stretches if they didn’t sleep in the same bedroom as their parents.
At 4 months, babies who slept alone had the longest stretches of uninterrupted sleep — by about 45 minutes, on average — though they slept about the same amount of time as babies who slept in their parents’ rooms.
At 9 months, babies in their own rooms slept 40 minutes longer at night and over 20 minutes longer overall, compared with those who were still sharing a room with their parents. Those differences disappeared at 12 months but reappeared later. When the researchers followed up at 2½ years, toddlers who began sleeping alone by 9 months slept 45 minutes longer per night, though total sleep time was roughly the same.