One rule every infant caregiver likely knows is that it’s safest for babies to sleep on their backs, not their stomachs or sides. On the surface, this sounds simple enough — back-sleeping is associated with a lower risk of Sudden Infant Death Syndrome (SIDS). But the rule can also leave parents and caregivers with questions. For example, if you have a baby who naturally rolls onto their side or just really prefers to sleep on their side, is that ever OK? When can babies sleep on their side without being unsafe?
The problem with side sleeping is that it makes it more likely for babies to roll onto their bellies. While SIDS tends to be associated with sleeping in a prone position, babies who slept on their sides have also succumbed to SIDS.
Though back sleeping is safest for babies, experts agree that there are caveats, and that side sleeping may not always be a hard “no,” depending on the circumstances and the age of the baby. Let’s take a closer look at the issue of side sleeping, including tips and advice on when babies can sleep on their side safely.
Why can’t babies sleep on their side?
Experts generally agree that babies should never be deliberately put to sleep on their sides. The main reasoning behind this recommendation is the risk of Sudden Unexpected Infant Death (SUID), which results in the tragic deaths of hundreds of babies per year. SUID is an umbrella term that includes infant deaths from SIDS, unknown causes and accidental strangulation or suffocation during sleep.
Stomach sleeping is particularly concerning and is a top risk factor for SIDS and SUID. This is because stomach sleeping can increase a baby’s risk of:
- Becoming overheated.
- Breathing in exhaled air, which can increase carbon dioxide in the baby’s body.
- Experiencing changes in heart and lung function, which can limit oxygen reaching the brain.
Side sleeping is problematic, too, because it increases the chances that a baby will turn onto their stomach. There’s also evidence that side sleeping in and of itself is a risk factor for SIDS. Research has found that babies put to sleep on their sides, who then turn onto their stomachs, face a higher risk of SIDS than babies who are routinely placed on their stomachs for sleep.
The key driver in reducing deaths of babies from SIDS has been placing infants on their backs to go to sleep. Back in the early 1990s, when physicians discovered that babies who slept on their backs were much less likely to die of SIDS, they began recommending that all babies sleep on their backs. Canada saw SIDS cases fall by 50% from 1999 to 2004 following the introduction of the Back to Sleep campaign in 1999.
What is the safest way for babies to sleep?
Putting your baby to sleep on their back is one of the most important ways to keep them healthy and safe during the newborn period, but safe sleep isn’t only about sleep position. It’s also about creating an overall safe sleep environment for your little one.
In addition to putting babies to sleep on their backs, advice from the Public Health Agency of Canada says you can keep babies safe during sleep by adopting the following practices:
- Choosing a firm, flat surface for the baby, with a tightly fitted sheet.
- Keeping the baby’s sleep space clear of loose objects, pillows, toys, blankets and crib bumpers or pads
- Keeping children comfortable at room temperature in simple, fitted sleepwear or using appropriate sleep sacks, and avoiding the use of loose or heavy blankets.
- Ensuring children do not overheat in their clothing.
Additionally, the official advice recommends placing the baby in a crib, cradle or bassinet in the same room as you for their first six months so you are aware of their movements, breathing and needs.
What if a baby rolls onto their side while asleep?
It’s clear that you shouldn’t put babies to sleep on their side, but what if they roll onto their side on their own? This definitely happens to many babies, leaving parents and caregivers to wonder if it’s necessary to move them onto their backs and risk waking them.
Some expert advice suggests that it’s usually fine to let babies stay on their sides once they are about four months old. According to official guidance, the risk of SIDS is at its highest by far when babies are less than four months old.
Some experts believe that when babies are capable of rolling over in their sleep — at age four months or over — they are out of the highest-risk period for Sudden Unexplained Infant Death (SUID) and can continue sleeping in a side position if they have naturally made their way there. If rolling over isn’t a capability they have acquired yet, and they still somehow end up on their side, some experts believe they can be left sleeping where they are. The main thing is always to place them to sleep on their backs in the first place and make sure their surroundings do not pose any risks.
Is there a way to prevent side sleeping for babies?
Some products, such as wedges and sleep positioners, claim to prevent rolling or side-sleeping, but these are considered unsafe. You can’t prevent a baby from rolling over onto their side once they are able to, and this kind of equipment puts babies at greater risk of suffocating or becoming caught underneath.
Official advice similarly warns that parents and caregivers should not use sleep positioners, nests, wedges, anti-roll products or other devices marketed to keep babies in a certain position during sleep.
If a baby frequently rolls onto their side, you might be wondering if there’s anything you can do to prevent it from happening. You don’t need to overthink this, and concentrating on putting the baby down safely — on their back — is the best way to avoid any issues.
When can babies safely sleep on their side?
When can you finally let a baby freely sleep on their side? The danger of succumbing to SIDS is much lower for babies once they reach the one-year mark. This means that from this point on, it’s safer to allow them to sleep on their sides.
This means that once a child is over 12 months old, they should be able to fall asleep on their side or even be placed to sleep in this position. This aligns with expert recommendations which state that babies should be placed to sleep on their back for both naps and night sleep during the first year (12 months) of life.
Of course, every baby is different. Certain conditions or health factors may make side sleeping unsafe even beyond 12 months of age. Safe sleep guidance should always be verified with a child’s doctor.
The bottom line
There are a lot of rules and guidelines when it comes to baby sleep. This can seem stressful, but it’s important to remember they are all in the name of keeping babies healthy and safe.
Babies who roll onto their sides or prefer to sleep on their sides may be able to stay in that position if they’re rolling on their own (which happens around the age of four months) or if they’re at least one year old. But it’s recommended that infants be put to sleep on their backs, on a firm and clear surface, every single time.
Always talk to a doctor before making changes to a baby’s sleep environment. If you have questions about side sleeping or safe sleep in general, reach out to your baby’s pediatrician.