Winter Warning: Blankets Pose Risk to Safe Infant Sleep
By Ashley Antle
Making sure your baby stays warm on a cold winter’s night is a natural instinct for any parent. While tucking them in with a soft, cushy blanket may seem like the obvious choice to keep them cozy, it can pose a risk of sudden unexplained infant death (SUID) for infants less than 1-year-old.
In nearly 30% of SUID cases, the cause is attributed to accidental suffocation or strangulation in bed, according to the Centers for Disease Control.
In 2023, Cook Children’s recorded 15 sudden infant unexplained deaths. All of them were caused by unsafe sleep conditions, which could mean a child was suffocated by a pillow, stuffed animal, another person in the bed, a too-soft sleeping surface or a loose blanket.
“In the colder months we often see parents adding lots of layers of clothing and extra blankets to keep a baby warm in bed,” said Samantha St. John, Community Health Program Coordinator at the Center for Community Health, led by Cook Children’s. “But our recommendations for safe sleep in the winter are the same as in the summer.”
In every season, babies should sleep alone, on their backs, and in a crib or pack n’ play with a firm surface and tight fitted sheet.
Alone means nothing in the bed but baby — no person, stuffed animal, pillow or blanket. All of these pose a risk of covering the baby’s nose and mouth. Because of their limited muscle strength and control, babies are not able to move the item off of their face or move their head away, leading to suffocation.
So what is a parent concerned about their baby’s comfort to do? 
St. John recommends a wearable blanket, also known as a sleep sack. Babies fit inside the sack, which has armholes, zips up to their neck and billows out down toward their feet.
“It’s an extra layer that is just like having a blanket but, when fitted and zipped properly, there is no risk of the blanket moving up around their face and causing suffocation,” St. John said.
Wearable blankets that allow a baby’s arms to be swaddled inside the sack can be used up to 8 weeks or when the baby starts to roll on their own, whichever comes first. Babies use their arms to roll over and need them free once they show signs of reaching this developmental milestone. Sleep sacks should be fitted according to the manufacturer’s recommendations based on the baby’s height, weight and age.
A good rule of thumb for adding layers for warmth is to match what the parent is wearing, plus add one layer.
“There is a risk of overheating when too many layers are added and the baby becomes too warm,” St. John said. “Babies usually run a little bit warmer than what we do. So the recommendations for how many layers to put them in is no more than one additional layer than what the parent is wearing. We’re matching the parent’s layer and then adding one more.”
For example, if the caregiver is in flannel pants and a flannel long-sleeve shirt for bedtime, then it would be appropriate to put the baby in a fleece long-sleeve onesie and then put a cotton sleep sack over that long-sleeve onesie.
Anything that can come off during sleep, like a hat, poses a risk, too. Avoid using a twin sheet to cover a crib mattress. If the too-big and ill-fitting twin sheet comes loose during sleep, the baby can become tangled. 
When you are bundling a baby up for a trip out of the house, be careful of puffy coats while they are riding in a car seat. Puffy coats make it difficult to tighten the harness as snug as it should be. In an accident, the loose harness can slide off the shoulders, creating a risk of ejection from the car seat.
St. John says to use a thin layer coat, like a zip-up sweatshirt jacket, instead.
“Another good option is to strap your older infant into their car seat and then put their jacket on backward,” St. John said. “So their arms will be through the armholes with the jacket laying on top of them. It gives them that warmth, but does not interfere with the harness so that it is still tight on their shoulders.”
By choosing the right layers and avoiding loose items in your baby’s crib, you’ll rest well knowing your little one is sleeping safe and sound in the long winter months ahead.
More about safe sleep from Cook Children’s Checkup Newsroom:
Safe Baby Sleep 
The Center for Community Health, led by Cook Children’s has collaborated on a campaign for infant sleep awareness since 2015. Working with community partners like the Fort Worth Fire Department and Tarrant Baptist Association, the Safe Baby Sleep Council distributes pack ‘n plays to families that need a place for their baby to sleep. For videos, educational resources and more information, go to Safe Baby Sleep (centerforchildrenshealth.org)
