The successful campaign to encourage babies to sleep on their backs has saved many lives by often preventing the tragedy of SIDS. But when babies sleep in the same position each night their heads can get flat. Over the 5 years of the Back to Sleep campaign, the number of babies with misshapen heads soared fivefold. Placing the baby's head at opposite ends of the crib each night, to encourage turning in different directions, can help prevent flat spots. If a problem does occur, it will often correct itself when the baby begins sitting upright most of the day. If not, the best age to correct a baby’s head shape (often with special helmets) is 6 to 12 months old.