April 2026
Can Newborns Sleep on Their Side
Newborns should sleep on their backs, not on their side, according to safe sleep guidance from pediatric organizations such as the American Academy of Pediatrics (AAP). Back sleeping reduces the risk of sudden infant death syndrome (SIDS) and is recommended for every sleep during the first year of life.
This does not automatically mean side positions are always unsafe, because side-lying can still be used safely when babies are awake and supervised. The key difference is whether the baby is sleeping or awake.
Why back sleeping is recommended
Tummy time means placing your baby on their stomach while they are awake and supervised. This position encourages babies to lift their head, move their arms, and build strength against gravity. It is different from sleep positioning, where babies should always be placed on their back. During tummy time, babies begin learning how to push up, turn their head, and engage their muscles. These movements support coordination and early motor control.
Tummy time is often described as a baby's first physical workout. Even short sessions contribute to development when repeated consistently. Over time, these small efforts build meaningful strength and they also play a direct role in preventing flat head syndrome (read: how important head shapes are) during the first months of life.
Why side sleeping is not recommended
Side sleeping is considered unstable for newborns. Babies placed on their side can easily roll onto their stomach during sleep. Because newborn muscles are still developing, they may not yet be able to reposition themselves safely if their breathing becomes restricted.
Why some newborns naturally roll to the side
Some newborns briefly roll onto their side during the first weeks of life because of a reflex sometimes called the newborn curl. This reflex usually fades within the first few weeks as muscle control changes. Therefore side-lying during the time the baby is awake feels natural and comfortable and can be done when the baby is awake and supervised. But caregivers should place or turn the baby on the back at the start of every sleep.
What doctors recommend for safe sleep
Safe sleep guidelines recommend placing babies on a firm mattress with only a fitted sheet. Soft bedding, pillows, sleep positioners, wedges, or rolled blankets should not be used in the crib. These items can increase the risk of unsafe sleep conditions.
A common myth about choking
Some parents worry that babies sleeping on their back may choke if they spit up milk. Pediatric research shows that healthy infants do not have a higher choking risk when sleeping on their backs. The airway anatomy and gag reflex help protect breathing even when babies spit up.
When side-lying can be helpful
Side-lying can be useful during awake time. Pediatric physiotherapists often use this position to support movement development and reduce pressure on the back of the head. These benefits occur when babies are awake and supervised, not while sleeping.
What pediatric experts explain
Pediatric sleep guidance from organizations such as the American Academy of Pediatrics and Johns Hopkins Medicine recommends placing babies on their back for every sleep during the first year of life. Pediatric physiotherapist Elly van der Grift explains, “Side-lying can support movement and comfort when babies are awake, but they should always be placed on their backs when it is time to sleep.”
When parents usually ask about side sleeping
Parents often ask about side sleeping when their newborn prefers turning the head one direction or seems more comfortable on the side. Instead of side sleeping, you can lay your baby on their side during playtime, even from nap to nap. Side-lying is indeed a strong tool to prevent flat head syndroom, as plagiocephaly and brachycephaly. Many parents choose this safe option: on their side when awake and on their back when asleep. By 6 months, many babies develop stronger head control and begin rolling, which naturally changes how they move during sleep.
Common questions parents ask
Why can't newborns sleep on their side?
Because side sleeping is unstable. A baby placed on their side, or on either of their sides, can easily roll onto the stomach before they are strong enough to move back safely.
How long can a newborn sleep on their side?
They should not sleep on their side at all. Side-lying is only for short periods while the baby is awake and supervised, including briefly on your chest.
Can newborns sleep on their side?
No, babies should always be placed on their back for sleep.
Can a newborn sleep on their side in a bassinet or swaddle?
No. Whether in a crib, bassinet or swaddle, newborns should always be placed on their back to sleep.
Is side-lying ever safe?
Yes, side-lying can be used when babies are awake and supervised.
Why do some newborns roll to their side?
A temporary newborn reflex can cause brief side rolling.
Does back sleeping cause flat head?
Only when the baby lays and sleeps more than 75% of the time on one side/spot of the head.
When can babies sleep in other positions?
Once babies can roll independently, they may change positions during sleep.
Writen by Elly van der Grift
Elly van der Grift is a pediatric physiotherapist with more than 30 years of experience helping families understand infant head growth and development.