Swaddle vs. Sleep Sack: Benefits, Drawbacks, Risks

Swaddle vs. Sleep Sack: Benefits, Drawbacks, Risks

Many parents turn to either swaddles or sleep sacks to keep their baby comfortable while sleeping. Swaddling also is used as a way to soothe a fussy newborn and promote sleep—especially as they adjust to life outside the womb.

“Swaddling is a traditional practice of wrapping a baby gently in a light blanket in a way that mimics the womb,” says Jessica Morse, MD, a newborn medicine pediatrician at Children's Health and assistant professor at UT Southwestern Medical Center, adding that there are different types of swaddle blankets, including breathable muslin or cotton blankets.

A sleep sack, on the other hand, is an alternative to traditional swaddling and is a specially-designed baby garment for secure sleeping. But deciding which is best for your baby isn't always simple. For this reason, we spoke with pediatric experts to find out the benefits and risks of swaddles vs. sleep sacks and how to determine which is right for you. 

What Is a Swaddle?

Swaddling refers to snugly wrapping your baby’s arms near their chest to recreate the sensation they had in the womb, explains Stephanie Napolitano, MD, a neonatologist at Nationwide Children’s Hospital. “Swaddling your infant can help soothe them by giving them boundaries that they developed inside the birthing parent.”

Traditionally, swaddling is done with a blanket, says Dr. Napolitano. “However, when we swaddle with a blanket and leave infants unobserved during sleep, it can become loose and unwrap as the baby moves, and the loose blanket can create a suffocation risk for an infant.”

For this reason, pre-made swaddles or wearable blankets were developed to provide infants that containment but with blankets that will wrap and secure, generally with wings or straps and Velcro.

“A pre-made swaddle is generally more convenient than using a blanket that needs to be specially wrapped and folded, but both serve the same purpose,” adds Rebekah Diamond, MD, an assistant professor of pediatrics at Columbia University, and the author of Parent Like a Pediatrician. 

Pros and Cons of Using a Swaddle

Swaddling an infant provides that tactile feedback needed to soothe or calm them in the safest way during sleep, says Dr. Napolitano. That said, there are some drawbacks to using a swaddle as well. Here’s an overview of the pros and cons of swaddling.

Benefits of Swaddling

Provides tactile feedback

Can be soothing and calming

Creates sensation of being in the womb

Promotes sleep

Drawbacks of Swaddling

Can pose challenges in trying to wake your baby from a deeper sleep

Increases risk of overheating

May interfere with breastfeeding if baby sleeps too long

Can be difficult to use correctly

Safety Considerations for Using a Swaddle

Typically, it’s recommended that you stop swaddling your baby when they show signs of being ready to roll over. Generally, this occurs around 3 to 4 months of age or older—though every infant is different.

“Once this is the case, babies should never be swaddled with their arms inside,” says Dr. Diamond. “Swaddles can still be used after this age if both of the baby's arms are free."

When you are using a swaddle, also make sure that the swaddle isn’t near your baby’s face or too tight around their chest or hips, adds Dr. Napolitano. “[Their] hips should have ample space to move and develop.”

There also is some evidence that swaddling may make it more challenging for babies to wake from a deeper sleep. And, while this extended snoozing may be attractive for sleep-deprived parents, this can interfere with breastfeeding and nutrition, as well as increase the risk of sudden infant death syndrome (SIDS). There also is a risk of overheating–especially if you notice damp hair, flushed cheeks, or even a heat rash.

You can reduce the risk of overheating by dressing your baby appropriately, says Dr. Napolitano. “A good rule of thumb is generally what you’re comfortable wearing, plus one layer.”

What Is a Sleep Sack?

A sleep sack is similar to a swaddle, but much less restrictive, explains Robert Quillin, MD, a board-certified pediatrician and medical director at Pediatrix Medical Group. “Sleep sacks have unrestricted arm movement, which can be sleeved or sleeveless [and] the lower portion is looser and allows your baby to move their legs more freely.”

Sleep sacks also don’t have the same ability to wrap tightly around a baby's torso and arms but instead has a pouch-like shape that babies can be zipped into, says Dr. Diamond. "A blanket or any loose cloth is unsafe for infant sleep, so sleep sacks replace blankets for added warmth and comfort."

Pros and Cons of Using a Sleep Sack

Because blankets pose a risk of suffocation for babies younger than 24 months, a sleep sack is a safer option, says Maria Lopez, a sleep expert and director of Sleep Sense en Espanol. “A sleep sack also keeps your child warm all night.” 

Here are some of the benefits and drawbacks of using a sleep sack:

Benefits of Using a Sleep Sack

Can be used even when your baby can roll

Safe for newborns

May be easier to use than a swaddle

Drawbacks of Using a Sleep Sack

Comes in limited sizes

May not be useful or safe once a baby can stand or becomes mobile

Safety Considerations When Using a Sleep Sack

According to Dr. Quillin, the same safety considerations that apply to a swaddle also apply to a sleep sack. “The weight or thickness of the blanket may really be the only potential safety concern when used correctly.” 

That said, when you choose a sleep sack, make sure that it's roomy enough for free movement, especially if your child can sit or stand up, says Lopez. “As with swaddles, do not use weighted sleep sacks, and avoid overdressing your child when using one. Make sure the fabric is appropriate for the weather to prevent overheating.”

How to Decide Between a Swaddle or Sleep Sack 

Choosing between a swaddle and a sleep sack when your baby is under 3 to 4 months of age—and they’re not yet rolling over—really comes down to personal preference and your goals. 

If you have a fussy baby who needs comfort and security during naps, you may want to swaddle them from time to time. But if your baby enjoys moving their arms and kicking their legs—even if they can’t roll over—they may prefer a sleep sack.

The weather and temperature of the room also should be considered. Swaddling in a warm room or during hot weather may cause your baby to overheat due to the restrictive nature of the swaddle. In these situations, a lightweight sleep sack might be a better option for nighttime sleeping—as long as you don’t overdress them.

Ultimately, though, Lopez recommends using age as the primary decision maker. “I do not recommend swaddling babies over 4 months, regardless of whether or not they have learned to roll over.” 

Swaddle Up Transitioning Collection 

When to stop swaddling and how to transition baby to arms-out sleeping

When to stop swaddling your baby

Congratulations, you've survived the first few months of a newborn, have them wrapped snuggly in a swaddle, and baby (may have) finally settled into a predictable sleep routine. And then comes baby's first major milestone, rolling, to undo all that hard work!

Many parents are apprehensive to unswaddle their baby once they reach the rolling milestone, for fear of what it will do for settling and sleep. What those parents may not know is that once a baby shows signs of rolling it is no longer safe to swaddle them, and the transition to arms-out sleeping must begin.

Why is it unsafe to swaddle a baby who is attempting to roll?

A baby who is ready to roll is transitioning out of the 'fencing reflex', an innate newborn mechanism designed to keep the body anchored on their back and prevent SIDS. Once this reflex starts to disappear, your baby would have built the necessary strength and muscle tone to hold their head up and roll their body over. A baby that is learning to roll from back-to-front needs their arms free to help roll back, and/or lift their neck and head sideways for clear and unobstructed breathing whilst face down.

What are the signs of attempting to roll?

Indicators that your baby is showing signs of rolling, and no longer requires a swaddle for sleeping include:

Attempting to roll body when unswaddled

Pushing up on hands during tummy time, lifting one hand off the ground

Fussiness when swaddled/fighting the swaddle when going on

Disrupted sleep

Disappearance of the startle (moro) reflex

Attempting to have hands free/up around their face when the swaddle is on

At what age will this happen?

While there is no set rule for the exact time to move through the transition from swaddle to arms-out sleeping, it typically starts between 3-6 months old. However, some babies may start earlier and some may take longer. You may be unsure of when exactly to make the transition, however you know your baby best. Follow the signs above and your baby's cues as the best way to get through this stage.

Between 4-6 months babies outgrow the startle (moro) reflex. If your baby is not yet rolling and still swaddled, but is no longer startling this may also indicate it is time to transition from swaddling.

How to safely transition your baby to arms-out sleeping in a sleeping bag

Some babies may struggle with this change in their sleeping environment. As such we recommend a two-step approach to transitioning:

Step One: Releasing one arm out of your baby's swaddle for all sleeps, to allow your baby time to become used to this new way of sleeping.

Step Two: After a week or so of one-arm-out sleeping, remove both arms from the swaddle. Expect some difficult sleeps during this phase, but stick with it and don't be tempted to re-swaddle them - they will adjust to the new sleep position.

Once your baby is rolling on their own, if they independently roll on to their tummy in their sleep with their arms out of a swaddle, you do not need to roll them back.

Pssst... If you anticipate that the transition to arms-out sleeping will be a challenge or are going through some resistance to the transition, we have a solution for you. We have designed the Butterfly Cardi to help in the transition from a swaddled sleeper to an arms-out dreamer, easier!
 

How to use the Butterfly Cardi for transitioning out of a swaddle

We recommend transitioning over a 10 day period. This should commence when your baby first shows signs of wanting to roll (not after they start rolling) for their safety.

DAY 1 - 3
Dress your baby in the Butterfly Cardi over their sleeping bag or Cocoon Swaddle Bag with their arms contained within the fold-over arm pockets for all their sleeps (day and night).

Use the press studs to adjust the firmness of the Cardi around the torso. If your baby has a strong startle reflex, start with a tight fit. If your baby has a low startle reflex, you can start with the looser fit.

DAY 4 - 7
After your little one is familiar with their new sleepwear addition, you can now take one arm out of the fold-over pocket for all their sleeps.

DAY 8 - 9
In this next stage, you can take their remaining arm out of the other pocket for all their sleeps.

DAY 10
On the final day, remove the Cardi altogether. Your baby is now sleeping, arms-out. Hooray!

For a visual guide on how this all comes together check out our How to Use the Butterfly Cardi Video:

Meet the Cocoon Sleep Set

All babies are wonderfully different, and just like adults, have different sleeping styles. The Cocoon Sleep Set is an all-in-one solution that gives your baby three different sleep-style options to choose from: Arms-in, Arms-out, or Hands-up.

Whichever your baby's preference, all three configurations are TOG-rated for warmth, and designed to keep your precious newborn safe and comfortable during sleep without needing loose blankets.

The Cocoon Sleep Set contains two of our most popular newborn sleepwear products.

The award-winning Cocoon Swaddle Bag is a TOG-rated zip-up swaddle that is easy to use, and difficult to escape from. With the ability for baby to sleep swaddled with arms in for babies with a high startle reflex, or alternatively arms-out for babies with a low startle reflex, the flexibility of the Cocoon Swaddle Bag is a sleep-saviour for many parents

The Butterfly Cardi is designed to be worn over your baby's swaddle or sleeping bag, and has two functions. It can be used as a hands-up sleeping option over the Cocoon Swaddle Bag or an arms-out sleeping bag, or as a transitional tool to help baby transition from swaddled to arms-out sleeping once they show signs of rolling. Babies who love the Butterfly Cardi usually have a lower startle reflex than those who like to be swaddled. Both products in the Cocoon Sleep Set are made with our signature GOTS-certified organic cotton and designed for the specific sleep needs and safety of newborns-6 months old.

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