Newborns should always sleep on their backs, on a firm and flat surface, with nothing else in the sleep area. That single setup, followed consistently for every nap and every bedtime, is the foundation of safe infant sleep. The details matter more than most parents realize, so here’s what the current evidence says about positioning, environment, feeding, and everything in between.
Always on the Back, Every Time
Back sleeping is the single most important thing you can do to protect your baby during sleep. This applies to all babies, including those born preterm and those with reflux. Side sleeping is not safe. Stomach sleeping is not safe. The recommendation holds for every sleep, whether it’s nighttime or a quick nap, and for every caregiver, whether that’s you, a grandparent, or a babysitter, until your baby turns one.
The risk of placing a back-sleeping baby on their stomach or side, even just once for a nap, is striking: it increases the chance of sudden infant death syndrome (SIDS) by up to 45 times. Once your baby can independently roll both ways (from back to stomach and from stomach to back), you can let them stay in whatever position they roll into on their own. But you should still place them on their back at the start of every sleep.
The Right Sleep Surface
Your baby’s mattress needs to be firm, flat, and level. Firm means it bounces back to its original shape quickly when you press on it, rather than conforming around your baby’s head or body. Flat means like a table, not curved like a hammock. Level means not propped at an angle. Any incline greater than 10 degrees is unsafe because a baby’s body can slide down and their head can slump forward, restricting their airway.
Safe options include a full-size crib, a bassinet, or a portable play yard, as long as each meets current federal safety standards from the U.S. Consumer Product Safety Commission. Cover the mattress with a fitted sheet and nothing else. That’s it. No blankets, no quilts, no pillows, no stuffed animals, no bumper pads, no mattress toppers. The phrase to remember is “bare is best.”
A few surfaces that are not safe for sleep, even though babies frequently fall asleep in them: car seats, strollers, swings, bouncers, rockers, and carriers or slings. If your baby dozes off in one of these, move them to a flat sleep surface as soon as you can.
What Goes in the Crib (and What Doesn’t)
Nothing should be in the crib except your baby and a fitted sheet. That means no loose blankets (even lightweight ones), no loveys, no wedges, no positioners, and no weighted blankets or weighted swaddles. Bumper pads have been directly linked to suffocation, entrapment, and strangulation deaths, and they’re no longer recommended regardless of the style.
Products marketed as preventing SIDS deserve particular skepticism. Wedges, positioners, and special monitors that claim to reduce the risk of SIDS do not meet federal sleep safety guidelines. Consumer heart and breathing monitors have not been shown to be effective at detecting or preventing SIDS. The safest approach is a bare, firm surface rather than any device designed to compensate for a less-safe setup.
Room Sharing Without Bed Sharing
Your baby should sleep in your bedroom but in their own separate sleep space for at least the first six months. This arrangement, room sharing without bed sharing, reduces the risk of SIDS by as much as 50%. Babies who sleep in a completely separate room are roughly 3 to 12 times more likely to die suddenly and unexpectedly than those who room share.
The key distinction is that bed sharing (sleeping on the same adult mattress) is not the same as room sharing. Adult beds pose serious risks of suffocation, entrapment, and overlay. A crib or bassinet placed next to your bed gives you the protective benefit of proximity without those dangers.
Room Temperature and Overheating
Keep the room between 68 and 78°F (20 to 26°C). A small fan on a low setting can help keep air circulating. Dress your baby in no more than one layer beyond what you’d wear comfortably in the same room. Your baby’s head and face should stay uncovered during sleep. Overheating is an independent risk factor for SIDS, so err on the side of slightly cool rather than too warm.
When Swaddling Is Safe (and When to Stop)
Swaddling can help calm newborns in the early weeks, but it has a firm expiration date. You need to stop swaddling as soon as your baby shows any signs of starting to roll over. For some babies, this happens as early as eight weeks. On average, rolling signs appear between two and six months. A swaddled baby who rolls onto their stomach cannot use their arms to push up or reposition, which creates a suffocation risk.
Signs that it’s time to transition out of the swaddle include: pushing up on hands during tummy time, attempting to roll during play, decreased startle reflex, lifting legs and flopping them to the side, or repeatedly breaking free of the swaddle wrap. If you see any of these, switch to a wearable blanket or sleep sack that leaves the arms free.
How Much Newborns Actually Sleep
Newborns sleep about 16 to 17 hours a day, but rarely more than one to two hours at a stretch. Their sleep cycles are fundamentally different from yours. About half of a newborn’s sleep time is spent in active (REM) sleep, compared to roughly 20 to 25% for adults. This means they stir, twitch, and wake more easily. It’s normal and not a sign that something is wrong with their sleep.
Because newborns have tiny stomachs, they need 8 to 12 feedings per day, or roughly one every two to three hours. If your newborn has been sleeping for more than four hours without eating, it’s generally appropriate to wake them for a feeding, especially in the early weeks before they’ve regained their birth weight. This frequent waking is biologically necessary and will gradually space out as your baby grows.
Reading Your Baby’s Sleep Cues
Catching the window when your baby is drowsy but not yet overtired makes a real difference. Early sleepy cues include a glazed or staring expression, yawning, losing interest in toys or faces, red or flushed eyebrows, droopy eyelids, ear pulling, and sucking on fingers. These signals mean your baby is ready to be put down.
If you miss that window, overtired cues look different: intense crying, rigidity or pushing away from you, general fussiness, irritability, and frequent eye rubbing. An overtired baby is paradoxically harder to get to sleep, so responding to those earlier, subtler signs tends to make the whole process smoother.
Pacifiers at Sleep Time
Offering a pacifier when you put your baby down for naps and bedtime is associated with a reduced risk of SIDS. You don’t need to replace it if it falls out after your baby is asleep. If you’re breastfeeding, it’s generally best to wait until nursing is well established (usually a few weeks) before introducing one. The pacifier should be plain, with no strings, clips, or stuffed animals attached to it.