The research is clear: Putting your baby to sleep on their back reduces their risk of sudden infant death syndrome (SIDS), according to the American Academy of Pediatrics (AAP). But down the road, you'll likely show up at your baby’s crib and find they’ve rolled onto their stomach.
So when can babies sleep on their stomach? The AAP recommends putting babies to sleep on their backs until at least 12 months of age (or older if they were preterm). But if they roll onto their bellies after you put them down—and you are certain they can easily roll from their stomach to their back— it’s fine for them to let them sleep in that position.
Here’s what else you need to know about baby sleep positions including when babies can sleep on their stomachs so you can rest assured your child will stay safe in their crib.
Risks Associated With Babies Sleeping on Their Stomach
In their first year, before they can roll back from their bellies easily on their own, it is not safe for babies to sleep face-down. Research shows that babies who are put down to sleep on their stomachs are more than twice as likely to die of SIDS than infants sleeping in other positions.
Younger Babies Are at Greater Risk
Even though SIDS can occur anytime during your baby's first year, most deaths from the syndrome occur in babies who are 1 to 4 months old.
When a young baby is sleeping on their belly, they are more likely to overheat, breathe in too much carbon dioxide, and suffocate, which are all events that are linked to SIDS.
Overheating
Research suggests that stomach sleeping may inhibit the ability to release heat and regulate body temperature among low-birthweight babies. This could lead to overheating, a risk factor for SIDS.
To reduce the risk of overheating, dress your baby in a lightweight wearable swaddle, keep their head and face uncovered, and watch out for signs your baby is too warm. If they are sweating or feel hot when you touch their chest, remove a layer or dial down the thermostat.
Rebreathing
When infants sleep on their stomachs, they may rebreathe expired air trapped in the bedding. That can lead to dangerously high carbon dioxide and low oxygen levels in their bodies, says Joan Becker Friedman, RN, certified child sleep consultant at Milwaukee, Wisconsin’s Pea Pod Sleep Consultants. This imbalance can harm brain and respiratory function.
Most babies will wake up and breathe fresh air, after which they are fine, she says. But some infants are slower to respond or will not be able to roll over, and will lose consciousness. Researchers think that some babies have brainstem abnormalities that hamper this arousal process, and they are hard at work to develop a system for identifying who those babies are.
The Truth About the Risk of Aspiration During Sleep
Many parents think stomach-sleeping infants are less likely to aspirate or accidentally breathe fluid into the lungs if they spit up while sleeping. But it turns out the opposite is true. “Due to the position of the trachea and esophagus, back sleepers are much less likely to aspirate if they spit up,” Becker Freidman says.
Suffocation
If a baby without sufficient head control rolls onto their stomach with their face buried into the crib mattress or bedding, that could pose a suffocation risk. You can help protect a young baby from suffocation by keeping the crib free from pillows or bumpers and avoiding sleeping wedges or weighted sleep sacks that could inhibit their movement.
Ditch the tight swaddle once they begin to roll, too. “If a baby is swaddled past the point of rolling, they could end up face- and nose-down on the mattress without the ability to wiggle to a free-breathing position,” says Becker Friedman.
When Is It Safe for Babies To Sleep on Their Stomach?
Experts say that most babies can be put to sleep on their stomachs once they have reached age 1. Before 12 months, always place your baby on their back for every sleep, whether it's naptime or nighttime. If your baby turns onto their tummy on their own, it's OK to leave them that way.
“When they are old enough to freely roll forward and back, they may choose to sleep on their stomach and that is OK,” says Elizabeth Murray, DO, a pediatrician at Golisano Children’s Hospital in Rochester, New York and fellow of the American Academy of Pediatrics. "The key here is the baby has to be able to easily move themself into and out of that position."
Tip
While waiting until the first birthday before placing babies to sleep on their stomach, there isn't a specific age or month when an infant is deemed ready to sleep on their stomach, says Becker Friedman. “It’s a matter of reaching developmental milestones.”
Once your baby is 1 year old, they should be fine to be put to sleep on their tummy, if that's what they prefer. If your baby was born prematurely, adjust their age based on their due date before considering them safe to sleep on their stomach.
Benefits of an Older Baby Sleeping on Their Tummy
Again, no baby under the age of 1 who has not yet mastered rolling back and forth should be put or left to sleep on their stomach. But once they are fully capable of rolling from their tummy to their back or have passed their first birthday, they may prefer the prone position.
“It’s very typical for babies to roll onto their stomach during sleep,” Becker Freidman says. “For many, it’s more comfortable than back-sleeping.”
Until then, only place your baby on their stomach during supervised tummy time when they are aware and alert. These three to five minute sessions, in which you put a wide-awake baby on their bellies, will strengthen their neck, shoulder, and arm muscles—and may help them master rolling, which can lead to safer sleep as they age.