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By the Peanutbean parent · checked against CDC, NHS and AAP guidance · how we fact-check

Swaddling: how to do it safely and when to stop

Last verified: July 18, 2026

The short answer: swaddling done correctly can calm a newborn and help them sleep. The rules that keep it safe: always on the back, thin fabric only, loose around the hips, no overheating, and stop the moment your baby shows any sign of trying to roll, which can be as early as 2 months. Never swaddle when bed-sharing or when your baby has a fever.

Why swaddling works, and why it needs rules

A thin blanket wrapped snugly around your baby can feel a bit like the womb, and the American Academy of Pediatrics says that when done correctly, swaddling can be an effective way to calm infants and help them sleep (AAP: Swaddling: Is it Safe for Your Baby?).

The honest part comes next, and it is worth reading even though it is uncomfortable. Swaddling may lower a baby’s arousal, meaning it is harder for them to wake up. That is exactly why it appeals to exhausted parents, and it is also why the rules matter: reduced arousal may be one of the main reasons babies die of SIDS (AAP). Swaddling is not banned, it is conditional. Here are the conditions.

The safety rules

• Back to sleep, every time. Studies have shown an increased risk of SIDS and suffocation when swaddled babies are placed on their stomach, or roll onto it. Never put a swaddled baby down on their front or side (AAP; Lullaby Trust: How to swaddle your baby).
• Thin fabric only. Use a lightweight material such as a thin muslin or thin cot sheet. Do not use blankets to swaddle, and never place extra bedding over a swaddled baby, because of overheating (Lullaby Trust).
• No weighted swaddles. Weighted swaddles and weighted blankets can put too much pressure on a baby’s chest and lungs (AAP).
• Minimal clothing underneath, head uncovered. No hat indoors, and do not swaddle above the shoulders, so loose fabric cannot cover the face (Lullaby Trust).
• Watch for overheating. Swaddling raises the chance of getting too hot. Warning signs: sweating, damp hair, flushed cheeks, heat rash, rapid breathing (AAP). Check the chest or the back of the neck, and keep the room at 16 to 20C. Our guide on what your baby should wear to sleep covers the layers.
• Never swaddle when bed-sharing, or when your baby has an infection or fever (Lullaby Trust).

Keep the hips loose

Swaddling too tightly around the legs is a real problem, not a theoretical one. Studies have found that straightening and tightly wrapping a baby’s legs can lead to hip dislocation or hip dysplasia, where the top of the thigh bone does not sit firmly in the hip socket (AAP).

The fix is simple: wrap snugly around the chest and arms, but leave enough room at the bottom for the legs to bend up and out, frog-style. The two-finger test helps at the top too: you should be able to fit at least two or three fingers between your baby’s chest and the swaddle (AAP; Lullaby Trust).

When to stop: the rolling rule

This is the deadline that matters. Stop swaddling as soon as your baby shows any signs of trying to roll over. Some babies start working on rolling as early as 2 months old, and every baby is different (AAP).

The reason is mechanical, and once you picture it you will not forget it: a swaddled baby who rolls onto their tummy cannot use their arms to push up or roll back (Lullaby Trust). Rolling practice often starts in the 17 to 26 week window, but the early attempts can show up well before that, so watch your baby, not the calendar.

Before rolling starts, arms in or arms out makes no known difference to SIDS risk. After rolling starts, arms must be free. A sleep sack that does not compress the arms and lets your baby move freely can be used for as long as you want (AAP).

Swaddle products, briefly

Swaddle blankets, sacks, and bags are everywhere. The Lullaby Trust does not vouch for any particular product, and their advice is practical: check the product meets safety standards, make sure it fits well, follow the manufacturer’s guidance (some size by weight, not age), and pick a lower tog rating to reduce overheating risk (Lullaby Trust). The same rule applies to compressing products as to fabric swaddles: once rolling starts, anything that pins the arms stops.

When to call your doctor

Swaddling questions are mostly prevention, but call your GP or 111 if:

• your baby has a fever (a swaddled baby with a fever should be unswaddled; see the thresholds in our fever guide)
• you notice your baby’s legs seem stiff, uneven, or one leg looks shorter, which are worth raising at any checkup
• your baby got stuck face-down while swaddled, even if they seem fine now, it is worth a same-day call for advice

And the house rule: your own concern is reason enough to ask.

Keep reading

• My baby rolls onto their tummy in their sleep
• Safe baby sleep and reducing the risk of SIDS
• What should my baby wear to sleep?
• Weeks 0 to 8: settling in
• All the first-year windows

Sources

• AAP: Swaddling: Is it Safe for Your Baby? (last updated July 2022)
• The Lullaby Trust: How to swaddle your baby (page last reviewed February 2025, updated April 2026)

Peanutbean provides general information for educational purposes only. It is not medical advice. Every baby develops at their own pace. Always talk to your pediatrician about your child’s health.