Babies should sleep on their backs for every sleep, naps included, until their first birthday. This is the clearest recommendation from the American Academy of Pediatrics (AAP), and it’s backed by decades of evidence. Since the back-to-sleep public health campaign launched in 1994, the SIDS rate in the United States dropped by more than 50%, falling from 1.34 per 1,000 births in 1991 to 0.64 per 1,000 by 2008.
That said, most parents hit a practical turning point well before 12 months: the baby starts rolling on their own. Here’s what that means for sleep position, and everything else you need to know about keeping your baby safe at night.
Why Back Sleeping Is Safer
When a baby sleeps on their back, the windpipe sits above the opening to the stomach. That means if milk or stomach contents come up, gravity keeps the fluid away from the airway. Flip a baby onto their stomach and the anatomy reverses: the stomach opening is now above the windpipe, so fluid pools right where it can block breathing.
Stomach sleeping also increases the risk of overheating and “rebreathing,” where a baby inhales their own exhaled air. This can cause carbon dioxide to build up and oxygen levels to drop, both of which affect the heart, lungs, and brain. Back sleeping is not associated with any of these risks.
The Choking Concern
Many parents worry that a baby sleeping face-up will choke on spit-up. It’s one of the most common reasons families try stomach sleeping. But the anatomy actually works in your favor: healthy babies naturally swallow or cough up fluids, and gravity helps keep those fluids out of the airway when a baby is on their back. Babies who sleep on their backs may actually be less likely to choke than those on their stomachs.
What to Do When Your Baby Rolls Over
Most babies start attempting to roll around 3 to 4 months, though some do it earlier. By 6 months, rolling from tummy to back is a milestone that 75% or more of babies have reached. Once your baby can roll both ways, from back to stomach and from stomach to back, you can let them stay in whatever position they choose during sleep.
The key rule doesn’t change, though: always place your baby down on their back. Every single time. If they roll onto their stomach after you’ve put them down, that’s fine as long as they have the strength to roll back. You don’t need to hover over the crib repositioning them all night.
When to Stop Swaddling
Swaddling and back sleeping go hand in hand for the first few months, but the moment your baby shows signs of trying to roll, swaddling needs to stop. A swaddled baby who rolls onto their stomach can’t use their arms to push up or reposition, which increases the risk of suffocation. The AAP is direct on this point: swaddling is no longer appropriate once rolling attempts begin.
Signs it’s time to transition out of the swaddle include pushing up on hands during tummy time, attempting to roll when unswaddled, fighting the swaddle at bedtime, or trying to get hands free and up near their face. The startle reflex that swaddling helps manage also fades around this time, so your baby may not need the swaddle for comfort anymore either.
The Sleep Surface Matters Too
Back sleeping works best when the surface underneath is firm, flat, and bare. That means a crib or bassinet mattress that springs back to its original shape when you press on it, covered only with a fitted sheet. Nothing else should be in the sleep space: no pillows, stuffed animals, blankets, bumpers, or loose bedding of any kind.
Soft surfaces like adult mattresses, couches, memory foam pads, and waterbeds are linked to higher rates of SIDS and suffocation, even when a baby is placed on their back. The combination of back sleeping and a firm, empty crib is what provides the most protection.
Weighted Products Are Not Safe
Weighted swaddles, weighted sleep sacks, and weighted blankets have drawn serious warnings from the Consumer Product Safety Commission, the CDC, the NIH, and the AAP. Because an infant’s rib cage isn’t rigid, even modest pressure can compress the chest, making it harder to breathe and harder for the heart to beat properly. There is also evidence that weighted sleep products lower oxygen levels, which may harm a developing brain. These products should not be used for infant sleep, period.
Preventing Flat Spots From Back Sleeping
Spending so many hours on their back can cause some babies to develop a flat spot on the skull, a condition called positional plagiocephaly. It’s common and almost always temporary, but you can reduce the risk with regular tummy time while your baby is awake and supervised.
Start tummy time soon after coming home from the hospital, even if it’s just a minute or two at a time. By about 7 weeks, aim for a total of 15 to 30 minutes spread throughout the day. Tummy time builds the neck, shoulder, and arm strength your baby will eventually need to roll over, and it takes pressure off the back of the head. You can also alternate which direction your baby’s head faces when you lay them down, so the same spot isn’t always pressed against the mattress.
Are There Medical Exceptions?
In rare cases involving severe reflux that hasn’t responded to other treatments, a doctor may recommend stomach or side sleeping. But this is considered a last resort, only after a full medical workup, and parents are counseled on the increased SIDS risk involved. For the vast majority of babies, including those with mild reflux, back sleeping remains the safest choice. If you’re unsure whether your baby’s situation qualifies as an exception, that’s a conversation to have with your pediatrician rather than a decision to make on your own.