Stop swaddling as soon as your baby shows any sign of trying to roll over. The American Academy of Pediatrics says some babies start working on rolling as early as 2 months, so what ends the swaddle is the sign, not a number of weeks on the calendar.
That is the short answer, and it is not the hard part. The hard part is that swaddling usually works. It works so well that stopping feels like choosing worse sleep on purpose, which is a strange thing to ask of somebody who has not slept properly since the hospital.
Why it works, and why that is also the risk
A thin blanket wrapped snugly around a newborn resembles the womb. The American Academy of Pediatrics says that when it is done correctly, swaddling can be an effective technique to help calm infants and promote sleep. Nobody argues with that half of it.
The half that does not get taught at the hospital is this. The AAP also says swaddling may decrease a baby’s arousal, so that it is harder for them to wake up, and that decreased arousal may be one of the main reasons that babies die of SIDS. The reason swaddling works and the reason it carries a risk are the same reason.
Sit with that for a second, because it explains why the advice sounds contradictory. Swaddling is not fine on Tuesday and dangerous on Wednesday. A baby who is slow to wake is safe while they are pinned on their back, and is not safe the moment they can get onto their front. Nothing about the blanket changes. The baby changes.
The sign that ends it
The AAP’s wording is to stop swaddling as soon as your baby shows any signs of trying to roll over. Not once they roll. Once they are trying.
In real life this arrives looking like a nuisance rather than a milestone. The rocking side to side inside the swaddle that you had filed under fussing. The leg that keeps hooking over. The shoulder that comes up off the mattress when they are cross about something. Most people notice it a week or so before they say it out loud, because saying it out loud means the swaddle is over.
Some babies start working on rolling as early as 2 months, according to the AAP, but every baby is different, so there is no date to write down in advance. There is only the first evening you look into the crib and think, that was nearly a roll. If the nights have been getting worse anyway and you are trying to work out why your baby keeps waking up, an almost roll inside a swaddle is worth ruling in early.
The reason it matters is specific. The AAP says some studies have shown an increased risk of SIDS and unintentional suffocation when babies are swaddled if they are placed on their stomach to sleep, or if they roll onto their stomach. A swaddled baby who ends up face down cannot push up and cannot turn their head freely, because their arms are inside the blanket. If babies are swaddled, the AAP says, they should be placed only on their back and monitored so they do not roll over.
Arms in or arms out
This is the most common workaround, so it deserves a straight answer. According to the AAP, there is no evidence with regard to SIDS risk related to the arms swaddled in or out.
Read that twice, because it cuts both ways. Arms out is not a proven safety upgrade that buys you three more weeks.
Where arms out actually earns its keep is the transition. A baby who has spent eight weeks with their hands pinned tends to have opinions about open air, and freeing one arm at a time is easier on everybody than a clean break on a random Tuesday night. That is a comfort tactic, not a safety extension. It is worth knowing which one you are doing, because the stop rule does not move either way.
How tight is too tight
Snug at the chest, loose at the hips. The AAP gives a check you can do one handed at 2am in the dark: you should be able to get at least two or three fingers between the baby’s chest and the swaddle.
The hip half is the part that catches people out. The AAP says babies who are swaddled too tightly may develop a problem with their hips, and that studies have found straightening and tightly wrapping a baby’s legs can lead to hip dislocation or hip dysplasia, an abnormal formation of the hip joint where the top of the thigh bone is not held firmly in the socket. The Pediatric Orthopaedic Society of North America, together with the AAP Section on Orthopaedics, promotes hip healthy swaddling, which allows the baby’s legs to bend up and out.
So the instinct to pull the legs straight and wrap everything tight, which is exactly what tired hands do at 3am because it holds better and stays put, is the one to unlearn. The AAP also says to use only a thin blanket. Thick ones are harder to keep flat and easier to get wrong.
Sleep sacks are not a loophole
This is where plenty of people quietly go wrong, because a sleep sack feels like the grown up version of a swaddle and the packaging almost never draws the line.
The AAP does prefer infant sleep clothing, such as layers of clothing or a wearable blanket or sleep sack, over blankets and other coverings for keeping a baby warm. But it splits the category in two. As with regular blanket swaddling, the AAP says the use of wearable blankets or sleep sacks that compress the arms, chest and body should stop once a baby shows signs of starting to roll over. Sleep sacks that do not swaddle and allow the baby to move freely can be used as long as you want.
The question is not whether it zips. The question is whether the arms and chest are held. If they are, it follows the swaddle rule and it ends when rolling starts. If the baby can move freely inside it, it can stay for as long as it fits.
Weighted products are a separate question with a shorter answer. The AAP says do not use weighted swaddles or weighted blankets, which can place too much pressure on a baby’s chest and lungs. That holds whether the thing is sold as a swaddle, a sleeper or a blanket, and it does not become fine at any point in the first year.
If the night ends with everyone in the bed
The AAP is unambiguous that it does not recommend bed sharing under any circumstances. The NHS takes a different route and publishes guidance for people who do it anyway, and one line in that guidance is directly about swaddling: if you share a bed with your baby, do not swaddle them, because baby sleeping bags are safer.
That is a real gap in most swaddling advice. A lot of nights end with a baby in a bed nobody planned to put them in. If that is your night, the swaddle comes off.
The heat problem
The AAP says swaddling can increase the chance your baby will overheat, and it lists what that looks like: sweating, damp hair, flushed cheeks, heat rash and rapid breathing. Overheating raises SIDS risk, which is why this belongs in a swaddling post and not only in a summer one.
The AAP’s rule of thumb is that your baby only needs one more layer than you would wear in the same environment to be comfortable. A swaddle is a layer. So is the sleepsuit underneath it. In August that is usually one layer too many, and the fix is to take something off rather than to give up on the swaddle entirely.
Where to check and what the signs actually look like is a question of its own, and it has its own answer here: is your baby too hot at night.
Daycare will probably say no
Better to know this before the first morning than at drop off. The AAP says some child care centers may have a policy against swaddling infants in their care, and it gives the reasoning rather than just the rule.
Part of it is the number of hands. A center usually has several caregivers who may have variations in swaddling technique, where at home one or two people do the same thing every night. The other part is more interesting. The AAP says studies show babies who are not usually swaddled react differently when swaddled for the first time at an older age, and may have a harder time waking up, which increases their risk of SIDS.
So it is not a policy aimed at your baby’s swaddle. It is a policy aimed at a room full of babies with different histories, wrapped by people who did not wrap them yesterday.
What to actually do
- Use a thin blanket. Not a thick one, not a folded one.
- Snug across the chest, with two or three fingers of room between the chest and the swaddle.
- Loose at the hips, legs free to bend up and out.
- On the back every time, for naps as well as at night.
- Nothing loose in the crib, including a swaddle blanket that has worked its way undone.
- Watch for the first sign of trying to roll, then stop. Free one arm first if the change is going badly.
- After that, a sleep sack is fine as long as it lets the arms and chest move.
The rest of the sleep picture sits alongside this rather than under it. If you are still building the routine, the newborn sleep basics cover the surface, the room and the layers in more detail.
When to ask your pediatrician
Nothing here is a diagnosis, and a pediatrician can examine your baby where a page cannot. Worth raising: a hip that clicks or clunks, legs that do not seem to move evenly, or a baby who is sweaty and flushed at night even after a layer has come off. Hips are checked at routine visits anyway, so the appointment already in your calendar is usually the right place for it.
The short version
- Stop at the first sign of trying to roll. The AAP says that can be as early as 2 months.
- The AAP says there is no evidence on SIDS risk either way for arms in or arms out. Arms out is for the transition, not for extra weeks.
- Two or three fingers between chest and swaddle. Hips loose enough to bend up and out.
- Sleep sacks that compress the arms and chest follow the same stop rule. Ones that let a baby move freely do not.
- No weighted swaddles, sleepers or blankets, at any age in the first year.
- Swaddling raises the chance of overheating. Sweating, damp hair, flushed cheeks, heat rash and fast breathing are the signs.
- If a night ends with the baby in your bed, the NHS says the swaddle comes off.
Sources
- American Academy of Pediatrics, HealthyChildren.org, “Swaddling: Is it Safe for Your Baby?”, Rachel Y. Moon MD FAAP and Danette Glassy MD FAAP, last updated 15 July 2022
- American Academy of Pediatrics, HealthyChildren.org, “How to Keep Your Sleeping Baby Safe: AAP Policy Explained”, Rachel Y. Moon MD FAAP
- NHS, “Reduce the risk of sudden infant death syndrome (SIDS)”, page last reviewed 25 November 2025
A note on this post. Written and edited by the NewBloom editorial team. NewBloom is not written by doctors, nurses or midwives, and nothing here is medical advice. We read the current guidance from bodies like the AAP, the CDC and the NHS and write down what it says, with every claim traced to its source and named in the sentence where it appears. General guidance is not the same as an answer about your baby. Your pediatrician, midwife or health visitor can see your child and we cannot, so anything here that raises a question about your own baby is a reason to ask them. If something is wrong right now, contact your doctor or your local emergency number. More about how we write these posts.