The American Academy of Pediatrics recommends that parents share a bedroom with an infant until the age of 1 to reduce the risk for sudden infant death, but a new analysis calls the guideline into question.

The study, in Pediatrics, included 230 infant-mother pairs. The 142 infants who were sleeping independently at 4 months slept, on average, 7.8 hours without waking, while those who were still room sharing slept seven hours. Independent sleepers had fewer night feedings and more consistent bedtimes than room sharers.

At 4 months, babies still sharing a room were more likely to have unapproved objects in their cribs (blankets, pillows, positioners); and at 4 and 9 months, parents were more likely to take room sharers into bed with them, also an unsafe practice. At age 30 months, infants sleeping independently by 9 months slept 45 minutes longer than room sharers.

“Beyond 6 months, SIDS is rare,” said the lead author, Dr. Ian M. Paul, a professor of pediatrics at Penn State College of Medicine, who said evidence was lacking to back the A.A.P.’s guidelines. “Separation anxiety peaks at 1 year. To all of a sudden change the sleeping location at that point is a recipe for trouble.”