How to swaddle safely, and when to stop

Newborns have a startle reflex. A sudden noise, or the feeling of being put down, makes their arms fly out, and that jolt is often enough to wake them. A snug swaddle keeps the arms in and seems to remind a baby of the womb. Plenty of newborns settle faster and sleep longer when they are wrapped.

What swaddling doesn't do is make sleep safer. It isn't a way to reduce the risk of SIDS, and done carelessly it can add risks of its own. Everything below follows the American Academy of Pediatrics' safe sleep guidance, linked at the end. If your baby was born early or has a medical condition, ask your pediatrician before you start.

The rules that matter

• Always on the back. A swaddled baby must be placed on their back to sleep, every time, for naps and at night. Never on the tummy or side.
• Snug at the chest, loose at the hips. You should be able to slide two or three fingers between the blanket and your baby's chest. The legs must be able to bend up and out.
• Not too warm. Dress your baby lightly underneath, and never cover their head.
• Nothing weighted. The AAP advises against weighted swaddles, weighted sleep sacks and weighted blankets for babies.
• Stop when they try to roll. Once a baby shows signs of rolling, swaddling has to end. More on that below.

How to swaddle with a muslin blanket

A square blanket about 110 to 120 cm across is the right size: big enough to wrap and tuck, not so big that there is extra fabric near the face. Muslin works well because it is light, breathable and has a little give. Our bamboo cotton muslin is 120 by 110 cm and the 100% cotton muslin is 110 cm square.

1. Lay the blanket flat in a diamond shape and fold the top corner down by about 15 cm (6 inches).
2. Place your baby on their back on the blanket, with their shoulders just below the folded edge. Nothing should come above their shoulders.
3. Bring one arm down alongside their body, slightly bent is fine. Pull that side's corner of the blanket across their chest and tuck it under their back on the opposite side.
4. Fold the bottom corner up loosely over the feet, leaving plenty of room for the legs to bend up and out. You can tuck the corner into the wrap near their shoulder, or leave it folded loosely underneath them.
5. Bring the other arm down, then pull the last corner across and tuck it under their back on the other side.
6. Check: two or three fingers fit between the blanket and the chest; the hips and knees can bend; the fabric is well clear of the face.

It gets quick with practice, and every nurse has a slightly different method. What matters is the result, not the exact folds.

Getting the hips right

A baby's hip joints are still soft in the first months. Wrapping the legs straight and tight together, the way babies were often swaddled in the past, can pull the hips out of position and increases the risk of hip dysplasia.

The fix is simple: keep the swaddle snug around the arms and chest and loose around the legs. When you check, your baby's knees should be able to fall apart into a frog-like position, with the hips bent up and out. The International Hip Dysplasia Institute has clear pictures of what to aim for.

Too hot, too cold

Swaddling adds a layer, so dress your baby lighter than you would otherwise. A bodysuit under the swaddle is usually plenty in a comfortable room. A good rule is no more than one layer more than you would need to feel comfortable yourself.

To check, feel the back of your baby's neck or their chest, not their hands and feet, which are often cool. Sweating, damp hair, flushed cheeks, a heat rash or fast breathing mean they are too warm, so take a layer off.

When to stop

Stop swaddling as soon as your baby shows signs of trying to roll over. Some babies start as early as two months. A swaddled baby who rolls onto their tummy can't use their arms to push up or turn their head, which is exactly the situation safe sleep advice is built to avoid.

Signs to watch for:

• rocking or rolling onto their side during tummy time or in the crib
• lifting their head and chest well off the floor during tummy time
• regularly breaking out of the swaddle, or wriggling around the crib in it

Some parents ease the change by leaving one arm out for a few nights, then both. That is fine early on, before any rolling. Once your baby is actually trying to roll, both arms need to be free, straight away.

Worth knowing: many daycares won't swaddle babies at all, so if your baby will be starting childcare, it may make sense to stop a bit earlier.

After the swaddle

Once the arms are out, the safest thing to sleep in is a wearable blanket, or sleep sack, with the arms free. What you shouldn't do is start using the swaddle blanket as a loose blanket in the crib. Until your baby is at least a year old, the AAP recommends a firm, flat mattress with a fitted sheet and nothing else in the sleep space: no loose blankets, pillows, bumpers or soft toys.

That includes loveys and plush comforters, including the ones we sell. They are lovely to cuddle and carry around while your baby is awake. Keep them out of the crib until after the first birthday.

A long second life

Once swaddling is over, a good muslin blanket is still one of the most useful things you own. It is a burp cloth, a nursing cover, a clean surface for a diaper change on a strange floor, and a mat for tummy time at a friend's house. It washes well and dries fast. Just don't drape one over a stroller to block the sun: it cuts the airflow, and the space inside can get hot quickly. A stroller sunshade does that job better.