Newborns should sleep on their backs, on a firm and flat surface, in a bare crib or bassinet, in the same room as a parent. That single sentence captures the core of safe newborn sleep, but the details matter. Every caregiver who puts a baby down, whether it’s a parent, grandparent, or babysitter, should follow the same practices every time the baby sleeps, day and night.
Always on Their Back
Back sleeping is the single most important thing you can do to reduce the risk of sleep-related infant death. Place your baby on their back for every sleep, including naps, until they turn one year old. Side sleeping is not considered safe either, since a baby on their side can easily roll onto their stomach.
Once your baby can roll both ways on their own (from back to belly and belly to back), you don’t need to reposition them if they flip over during the night. Most babies reach this milestone somewhere between 4 and 6 months. Until then, always start them on their back.
What Goes in the Crib
The simplest rule: bare is best. The only things in your baby’s crib or bassinet should be a firm, flat mattress and a fitted sheet. That’s it. No pillows, no blankets, no stuffed animals, no bumper pads, no sleep positioners. Young babies often cannot lift their heads to pull away from soft objects near their face, which creates a suffocation risk.
Weighted blankets and weighted swaddles are also unsafe for infants. If you’re worried about your baby being cold, dress them in a sleep sack or a one-piece sleeper instead of adding loose bedding.
Choosing a Safe Sleep Surface
The mattress should be firm enough that it holds its shape when your baby lies on it. If the surface indents or conforms around your baby’s head, it’s too soft. Memory foam mattresses and adjustable-firmness mattresses can create a pocket around a baby’s face, increasing the risk of suffocation.
The surface also needs to be flat. Federal safety standards require that infant sleep products have a sleep surface angled no more than 10 degrees from horizontal. That means inclined sleepers, rockers, swings, and car seats are not safe sleep surfaces, even if your baby falls asleep in them. If your baby dozes off in a car seat or swing, move them to a flat crib or bassinet as soon as you can.
Stick with a safety-approved crib, bassinet, or play yard. The mattress should fit snugly inside the frame with no gaps where a baby could become wedged.
Same Room, Separate Surface
Room sharing, meaning your baby sleeps in your bedroom but on their own surface, is recommended for at least the first six months and ideally for the first year. Having your baby nearby makes nighttime feeding easier and is protective against sleep-related death.
Bed sharing is a different matter. Despite being a common practice for many families around the world, current evidence has not been able to identify circumstances under which sharing an adult bed with an infant is safe. Adult mattresses, pillows, and blankets all pose suffocation and entrapment risks for a small baby. And couches and armchairs are especially dangerous. If you’re feeding your baby at night and think you might fall asleep, doing so in your bed (with pillows and blankets removed beforehand) is less risky than on a couch or recliner.
Room Temperature and Overheating
Keep the room between 68 and 72°F (20 to 22°C). Overheating is a known risk factor for sleep-related infant death. A good check: if you’re comfortable in a T-shirt, your baby is likely fine in a single layer plus a light sleep sack. Feel the back of their neck or their chest. If the skin feels hot or sweaty, they’re overdressed.
Avoid hats indoors. Babies regulate heat partly through their heads, and covering it during sleep can cause them to overheat without you realizing it.
When to Stop Swaddling
Swaddling can help calm a newborn’s startle reflex and improve sleep in the early weeks, but it has an expiration date. You need to stop swaddling as soon as your baby shows any signs of rolling over. For some babies this happens as early as 8 weeks, though the typical range is 2 to 6 months.
Signs it’s time to transition out of a swaddle include: pushing up on their hands during tummy time, lifting their legs and flopping them to the side, starting to roll during playtime, or repeatedly breaking free of the swaddle. A baby who rolls onto their stomach while swaddled cannot use their arms to push up or reposition, which is dangerous. Transition to a wearable blanket or sleep sack with arms free.
How Much Newborns Actually Sleep
During the first month, babies sleep roughly 16 hours per day, but never in long stretches. Newborn sleep is split about equally between REM (active sleep, when you may notice twitching or eye movement behind closed lids) and deeper non-REM sleep. Their sleep cycles are short, which is why they wake so frequently.
There’s no way to force a newborn into a predictable schedule in the early weeks. Hunger, not the clock, drives their waking. Most newborns sleep in stretches of 2 to 4 hours, waking to eat around the clock. By around 3 to 4 months, many babies start consolidating more sleep into nighttime hours, though this varies widely from one baby to another.
Pacifiers and Other Protective Factors
Offering a pacifier at bedtime and naptime is associated with a lower risk of sleep-related death. If you’re breastfeeding, it’s generally fine to introduce a pacifier once feeding is well established. If the pacifier falls out after your baby falls asleep, you don’t need to put it back in. And don’t force it; if your baby refuses, skip it.
Breastfeeding itself also provides a protective effect. Even partial breastfeeding reduces risk compared to no breastfeeding at all. Keeping up with your baby’s immunization schedule and avoiding smoke exposure (during pregnancy and after birth) are additional factors that lower risk.
Making It Work Every Night
The hardest part of safe sleep isn’t knowing the rules. It’s following them at 3 a.m. when you’re exhausted and your baby will only sleep on your chest. A few practical strategies help: set up your baby’s bassinet right next to your bed so you barely have to move during night feeds. Have a sleep sack ready to go so there’s no temptation to toss a blanket over a cold baby. And talk to every caregiver, including grandparents and daycare providers, about back sleeping on a bare surface. Babies who are used to sleeping on their backs and are then placed on their stomachs by an unfamiliar caregiver face an especially high risk.
Safe sleep practices apply to every sleep, not just nighttime. Naps on the couch, in a bouncer, or in a parent’s arms after a feeding all carry risk if the baby is left in that position. The safest spot is always the same: flat on their back, in their own sleep space, with nothing else around them.