Can Babies Sleep on Their Side?

Your baby was on their back when you laid them down, and now they’re curled up on their side. It’s common, and it’s easy to wonder whether side sleeping is a safe middle ground between back and tummy. It isn’t, at least not until your baby can roll both ways on their own. Until then, every nap and every night should start on their back, and if you find your baby on their side, gently turn them onto their back. The American Academy of Pediatrics (AAP) says side sleeping is just as risky as stomach sleeping, because a baby on their side can easily tip onto their tummy. Once your baby rolls from back to tummy and back again by themselves, usually around 4 to 6 months, you can let them stay in the position they choose.

If you’re worried about how your baby sleeps, ask your pediatrician first. This guide follows the AAP’s safe sleep guidance, but only your doctor knows your baby. If your baby was born early, always turns their head one way, or has reflux or another condition, talk to your doctor before relying on general advice, including tips from family or online forums.

Can babies sleep on their side, shown by an empty bassinet with a fitted sheet beside a parent's bed — Can babies sleep on their side? Not before they can roll both ways, so every sleep should start on their back in a bare bassinet like this. Can babies sleep on their side? Not before they can roll both ways, so every sleep should start on their back in a bare bassinet like this.

Side Sleeping by Age: What to Do

Age (roughly)	What to do if you find your baby on their side
Newborn to about 3 months	Gently turn them onto their back every time
About 3 to 6 months, rolling one way only	Stop swaddling. Keep turning them onto their back
Rolls both ways on their own (often 4 to 6 months)	Place on back to start. They can stay on their side if they roll there
1 year and older	Safe sleep guidance for babies covers the first year. Toddlers can sleep in any position

Go by what your baby can do, not by age alone. Some babies roll both ways early, others much later.

The NHS gives the same advice. It says to move your baby onto their back if they roll, until they can roll onto their front and back again by themselves. See the NHS page on reducing the risk of SIDS.

Why Side Sleeping Is Risky for Young Babies

Side sleeping was once thought to be safe, but research showed it carries a higher risk of sudden infant death syndrome (SIDS) than back sleeping. Today the AAP’s safe sleep guide is clear that side sleeping is not safe, because a baby on their side can easily roll onto their tummy. Every sleep should start on the back.

There are two main reasons.

It’s an unstable position. A young baby on their side can easily tip forward onto their tummy, and they can’t yet lift or turn their head well enough to get their face clear of the mattress.
It leads to tummy sleeping. Once face down, a young baby can breathe back in their own exhaled air and may not wake up to move. That’s the same risk that makes stomach sleeping unsafe in the early months.

The risk matters most when it’s highest. Most SIDS deaths happen between 1 and 4 months, and more than 90% happen before 6 months, according to NIH Safe to Sleep. For the full explanation of tummy sleeping and when it becomes safe, see our guide on when babies can sleep on their stomach.

Newborns Who Keep Ending Up on Their Side

No. Newborns should always be placed on their backs to sleep, and if they end up on their side, you should gently turn them back.

That said, a newborn tipping onto their side is very common, and it doesn’t mean your baby is rolling over. In an r/Parenting thread, a mom said her 2-week-old ended up on his side at every sleep, even swaddled. One parent explained that newborns tuck their legs up into a curled position, which shifts their balance and tips them sideways. For their own baby, it faded by about a month old.

A few practical points help with a newborn side sleeper.

Keep laying them on their back. As another parent in the thread put it, there’s not much else you can do, and that’s okay.
Never prop them. Rolled towels, wedges or positioners to hold a baby on their back or side are not safe and can cause suffocation.
Alternate their head position. Lay your baby with their head at the opposite end of the crib on alternate nights, since babies tend to turn toward light and sound.
Mention it at a checkup. If your baby always turns to the same side, ask your pediatrician to check for torticollis, a tight neck muscle that’s easy to treat with stretches when caught early.

Side Sleeping in a Swaddle

No, and swaddling makes side sleeping riskier. A swaddled baby who tips from their side onto their tummy can’t use their arms to push up or reposition. Always place a swaddled baby on their back, and stop swaddling as soon as your baby looks like they’re trying to roll, which the AAP says usually starts around 3 to 4 months but can happen earlier. Switch to a sleeveless sleep sack once you stop.

What to Do If Your Baby Rolls Onto Their Side While Sleeping

If Your Baby Can’t Roll Both Ways Yet

Gently turn them onto their back. You may have to do this many times a night for a while, especially as your baby starts practicing rolling. Plenty of supervised tummy time during the day helps your baby build the strength to roll both ways sooner.

If Your Baby Rolls Both Ways on Their Own

Once your baby can roll from back to tummy and tummy to back by themselves, you don’t need to keep turning them. The AAP says babies who roll both ways comfortably can stay in the position they move into. Keep placing them on their back at the start of every sleep, and keep the crib bare.

When Side Sleeping Becomes Okay

Babies can sleep on their side once they get there on their own and can also roll back. For most babies, that’s somewhere between 4 and 6 months, though it varies. Some websites suggest turning babies back until their first birthday, but the AAP and NHS both say you can stop repositioning once your baby rolls both ways. If you’re unsure whether your baby is a confident roller, ask your pediatrician.

What If You’re Watching?

Not for sleep while they’re too young to roll both ways. Watching doesn’t remove the risk, since it’s easy to doze off or look away, and a young baby can tip onto their tummy quietly.

Side-lying while your baby is awake is a different thing. Playing on their side on a firm floor while you watch is a good way to build strength and give the back of their head a break from pressure. If your baby falls asleep during side-lying play, move them onto their back.

Napping on Your Chest

While you’re fully awake and alert, holding your baby on your chest is fine, whichever way their head is turned. The risk is falling asleep with your baby on you, especially on a sofa or armchair, where the AAP says the risk of sleep-related death rises sharply. If you feel drowsy, put your baby on their back in their own crib or bassinet.

In a Bassinet, Crib or Pack and Play

The same rule applies in a bassinet, crib or pack and play. Place your baby on their back, keep the space bare, and turn them back if they roll before they can roll both ways. Bassinets are usually outgrown around the time babies start rolling, so if your baby is starting to roll onto their side, it may be time to move to a crib. If you’re choosing one now, our guide to the best bedside bassinets covers safe options.

What About Reflux, Spit-Up and Choking?

Many parents worry that a baby on their back might choke on spit-up, and turn them on their side to prevent it. The AAP says even babies with reflux should sleep flat on their backs, unless your doctor gives specific advice for a medical condition. Healthy babies have a gag reflex and airway anatomy that protect them when lying on their backs. Side sleeping doesn’t lower the choking risk, and it raises the risk of rolling onto their tummy.

Frequently Asked Questions

No. Short naps carry the same risks as long ones, so place your baby on their back for every sleep, however short.

Let them fall asleep however works, then lay them on their back once they’re drowsy or asleep. A consistent bedtime routine, a dark room and white noise outside the crib can help them settle on their back.

Some studies found side sleeping slightly less risky than stomach sleeping, but the AAP advises against both, because babies on their sides so easily end up on their stomachs. Back sleeping is the only safe position to start every sleep.

No. Rolled towels, wedges and positioners are suffocation hazards and should never be in a baby’s sleep space.

The Bottom Line

Side sleeping only becomes safe once your baby can roll both ways on their own, which for many babies is somewhere between 4 and 6 months. Before that, place your baby on their back for every sleep, turn them back if they tip onto their side, stop swaddling once they show signs of rolling, and never use anything to prop them. A newborn who keeps ending up on their side is usually just curled up, not rolling, but keep turning them back and mention it at your next checkup.

This article is for general information only. Every baby is different, and it can’t replace advice from a doctor who has examined your child. If you’re worried about your baby, contact your pediatrician or emergency services right away.