A baby should not sleep with a blanket until they are at least 12 months old, according to the American Academy of Pediatrics (AAP). Introducing a blanket before 12 months increases the risk of accidental suffocation and sudden infant death syndrome (SIDS). Many experts recommend waiting until the baby can move the blanket away from their face on their own, which is typically around 12 months or even later, sometimes up to 18 months. Until then, safer alternatives like swaddling, sleep sacks, or layering clothing are advised to keep a baby warm during sleep.