The safest way to put a baby in a crib is on their back, on a firm and flat mattress with nothing else in the sleep space. But the physical act of transferring a sleeping or drowsy baby without waking them is what most parents actually struggle with. Getting this right involves your technique during the transfer, how you set up the crib, and how you adjust your approach as your baby grows.
The Physical Transfer: Step by Step
The moment you lower a baby into a crib, they often startle awake, arms flinging outward, and start crying. This is the Moro reflex, an involuntary response triggered when a baby senses a sudden loss of support or a falling sensation. It’s strongest in the first three to four months and is the main reason crib transfers fail.
To work around it, keep your baby’s body pressed close to your chest as you lean over the crib and lower them down. Move slowly and deliberately. Place their bottom and lower back on the mattress first, then gently guide their head down. The key moment comes after their body touches the mattress: keep both hands on them, one on their chest and one on their side, for several seconds. Then lift your hands away one at a time, slowly. This prevents the free-falling sensation that triggers the startle. If your baby stirs, a gentle steady pressure on their chest for another few seconds often settles them back down without needing to pick them up again.
Drowsy but Awake
Pediatric sleep specialists at Mount Sinai recommend placing babies in the crib while drowsy but not fully asleep. The goal is to let your baby practice the skill of falling asleep independently, which is an early form of self-regulation. A baby who always falls asleep being rocked, fed, or held will expect those conditions every time they wake during the night, which all babies do multiple times.
This doesn’t mean dropping a wide-awake baby into a crib and walking away. You’re aiming for that heavy-lidded, relaxed state where their eyes are fluttering closed but haven’t fully shut. There will likely be some fussing. That’s normal and not a sign that something is wrong. Over time, babies who practice this skill tend to sleep longer stretches because they can put themselves back to sleep when they wake between cycles.
What Goes in the Crib (and What Doesn’t)
The only things that belong in a crib are a firm, flat mattress and a fitted sheet. No blankets, no pillows, no bumper pads, no stuffed animals, and no positioning devices. The Consumer Product Safety Commission specifically warns against weighted blankets and weighted swaddles in any infant sleep space.
Crib wedges and inclined inserts are another common temptation, especially for babies with reflux. Parents understandably want to prop their baby at an angle to reduce spit-up. But research published in the National Library of Medicine found that inclines between 10 and 28 degrees made no significant difference in regurgitation episodes, fussiness, or comfort compared to lying flat. The AAP explicitly recommends against inclined sleep surfaces because they introduce suffocation risk without providing a meaningful benefit.
Room Conditions That Help
A baby who is too warm will sleep restlessly and wake more easily during a transfer. The recommended room temperature for infant sleep is 60 to 68°F (16 to 20°C). To check whether your baby is overheating, feel their chest or the back of their neck. Hands and feet that feel cool are normal and not a reliable indicator. If their chest feels hot or sweaty, remove a layer of clothing or switch to a lighter sleep sack.
Managing the Startle Reflex With Swaddling
Swaddling a newborn with arms snug against their body reduces the Moro reflex and makes crib transfers dramatically easier. But swaddling has a hard expiration date: the moment your baby shows any signs of rolling. Common early signs include rocking their hips side to side, twisting one leg across the body, reaching with both arms to one side, or holding their head up longer during tummy time. Some babies show these signs as early as eight weeks, though four months is more typical.
Once you see rolling signs, your baby’s arms need to be free. Many parents transition gradually by unswaddling one arm for a few days before freeing both. A wearable sleep sack with open arms is the standard replacement. These keep babies warm without restricting movement, and they’re safe for rolling.
Adjusting the Crib as Your Baby Grows
Most cribs have three or four mattress height settings, and using the right one matters more than many parents realize. The Cleveland Clinic recommends this timeline based on developmental milestones rather than age alone:
- Newborn to about 4 months: Highest mattress setting. This makes transfers easiest on your back since you don’t have to lean as far into the crib.
- Around 6 months (sitting, commando crawling, or getting on hands and knees): Middle setting. Lower the mattress before your baby can do these things, not after.
- Around 9 months (pulling to stand or any standing): Lowest setting. Even if your baby can’t stand independently yet, any standing means the mattress needs to come all the way down. A high mattress at this stage is a serious fall risk.
With the mattress on the lowest setting, the transfer technique changes. You’ll be leaning deeper into the crib, which can strain your back. Bending at the knees rather than the waist helps, and by this age most babies are better at being placed down without startling.
Moving From a Bassinet to a Crib
Most babies transition from a bassinet to a crib between 3 and 6 months. Bassinets typically have a weight limit of 15 to 20 pounds, but weight isn’t the only trigger. If your baby can roll over, push up on their hands and knees, or grab the sides of the bassinet, they’ve outgrown it regardless of weight. Bassinets should not be used past 6 months under any circumstances.
If your baby has been sleeping well in a bassinet and resists the crib, the change in space is usually the issue. You can ease the transition by using the crib for naps first while keeping the bassinet for nighttime, then switching over fully once your baby adjusts. Placing the crib in your room during the transition can also help, since the familiar sounds and smells stay the same even though the sleep surface has changed.
When Transfers Keep Failing
Some babies wake up every single time they’re placed in the crib no matter how slow or careful you are. A few adjustments can help. Warming the crib sheet with a heating pad before the transfer (remove it completely before placing the baby down) eliminates the shock of a cold surface. Placing a worn t-shirt of yours under the fitted sheet for a few minutes before removing it can leave a familiar scent. And timing matters: attempting the transfer during deep sleep, roughly 20 minutes after a baby falls asleep when their limbs are fully limp, gives you a better window than trying during light sleep when their eyes are still darting beneath their lids.
The drowsy-but-awake approach sidesteps the transfer problem entirely over time. A baby who learns to fall asleep in the crib doesn’t need to be transferred at all. It takes consistency and some patience with fussing, but most families who stick with it for a week or two see a noticeable shift.