Written by Sarah Mitchell, the founder of Helping Babies Sleep and author of the #1 bestselling book The Helping Babies Sleep Method: The Art and Science of Teaching Your Baby to Sleep. A retired chiropractor with a Bachelor of Kinesiology and a Doctor of Chiropractic degree, Sarah is also a Certified Lactation Counselor. She has worked with over 1,000 families across the San Francisco Bay Area and virtually nationwide over more than twelve years in practice.
It's one of the first things we picture when we imagine a sleeping baby: tucked in under a soft, cozy blanket. So it can feel strange to hear that your baby shouldn't have one at all.
This post is for parents of newborns, babies and toddlers up to age 3 who are wondering when blanket safety stops being a worry, when a blanket is actually okay, and what to use in the meantime to keep your little one warm.
The Short Answer: When Can My Baby Sleep With a Blanket?
Babies should not sleep with a loose blanket during the first year. The American Academy of Pediatrics (AAP) recommends keeping soft objects and loose bedding out of your baby's sleep space until at least 12 months of age. Until then, a wearable blanket, also called a sleep sack, is the safest way to keep your baby warm.
And here's what most blanket safety guides won't tell you: even after 12 months, a sleep sack is usually the better choice. Not just for safety, but for sleep. I'll explain why below.
What the AAP Safe Sleep Guidelines Say About Blankets
The AAP's safe sleep recommendations are designed to reduce the risk of Sudden Infant Death Syndrome (SIDS) and other sleep-related infant deaths. For the first year, the AAP recommends:
- A firm, flat sleep surface with a fitted sheet only
- No loose blankets, quilts, pillows, bumper pads or soft toys in the sleep space
- A wearable blanket or sleep sack instead of loose bedding to keep your baby warm
- No weighted blankets or weighted sleep sacks, which the AAP warns can place too much pressure on a baby's chest and lungs
- Avoiding overheating
These aren't overly cautious suggestions. They're built on decades of infant safety research, and I follow them with every family I work with.
Why Is a Blanket Unsafe for a Baby Under 12 Months?
Even a light blanket tucked over just the lower half of your baby's body carries risk. Babies move a lot in their sleep, and they can easily kick or wriggle a blanket up over their face.
In the first year, most babies don't yet have the motor control or strength to push a blanket away from their airway. That's why the main risks of loose bedding are suffocation and strangulation.
This applies to all loose bedding: lightweight muslins, a swaddle blanket that has come loose, crib quilts and that beautiful knitted blanket from Grandma. If it's loose in the crib, it isn't safe yet.
This is also why the swaddle has to come off completely once your baby starts trying to roll. A swaddle that has loosened during the night becomes a loose blanket.
🔗 Swaddling Guidelines: When to Start, When to Stop →
What to Use Instead of a Blanket: Sleep Sacks
You don't need a loose blanket to keep your baby warm. A wearable blanket, or sleep sack, zips or snaps around your baby so there is nothing loose in the crib. It can't be kicked off, pulled over the face or tangled around little arms and legs.
It's the one item I recommend to every family I work with, whatever the season. And if you're moving out of the swaddle, the sleep sack is the natural next step.
When choosing one, check two things:
- The neck and armholes fit snugly, so your baby can't slip down inside the sack.
- It's not weighted. The AAP recommends against weighted sleep sacks and blankets.
How to Choose a Sleep Sack TOG Rating
Sleep sacks are rated by TOG, a standard measure of how warm a fabric is. Matching the TOG to your baby's room temperature, not just the season, is one of the easiest sleep wins there is.
- TOG 0.5: rooms above 75°F (24°C). Warm summer rooms. A 100% cotton sack works well here.
- TOG 1.0: rooms 69–74°F (20–23°C). A good year-round option in temperature-controlled homes.
- TOG 2.5: rooms 61–68°F (16–20°C). Cooler rooms and winter nights. Merino wool regulates temperature beautifully.
The AAP's main concern is overheating, so dress your baby in no more than one layer more than you'd be comfortable in. Signs your baby is too warm include sweating, damp hair, flushed cheeks and a heat rash. In very cold rooms, you can add snug-fitting clothing underneath the sleep sack.
For room temperature, darkness, white noise and the rest of a safe, sleep-friendly space:
🔗 Baby Sleep Environment Checklist: How to Create an Ideal Space →
Why Breathable Fabrics Matter, Especially for Newborns
Newborns aren't very good at regulating their own body temperature yet. They can't shiver effectively to warm up, they rely on a special type of fat (brown fat) to make heat, and their large surface area compared to their tiny bodies means they lose and gain heat quickly (review of newborn thermoregulation). That makes them more vulnerable to both getting chilled and overheating than older babies.
That's why I always look at the fabric, not just the TOG. Natural fibers like 100% cotton and merino wool absorb moisture, so if your baby sweats, it's pulled away from their skin instead of sitting on it. In one study of adults sleeping in a warm room, merino wool sleepwear led to less disrupted sleep than polyester. Research on babies is limited, but because newborns can't regulate their temperature well, I prefer breathable natural fibers and avoid heavy synthetic fleece.
For a full breakdown of how to dress your baby for every season:
🔗 How to Dress Your Baby for Winter Sleep →
Can My 1-Year-Old Sleep With a Blanket?
At 12 months, your baby can technically sleep with a blanket. But I still recommend sticking with the sleep sack, and here's why.
Toddlers kick blankets off. Constantly. And when your child gets cold in the early hours, they wake up.
This matters more than most parents realize. Body temperature naturally drops in the early morning hours, and that's also one of the most common windows for early wake ups. A toddler who has kicked off their blanket at 4:30am is a toddler who is likely to be up for the day at 5.
A sleep sack takes this variable away completely, because it can't be kicked off.
I kept both of my own children in sleep sacks until about two and a half, when they moved to a toddler bed. At that point, a sleep sack with leg holes (sometimes called a footed sleep sack or wearable blanket with legs) gives a newly mobile toddler more freedom while still keeping them covered all night.
Blankets, Early Wake Ups and The Helping Babies Sleep Method
In The Helping Babies Sleep Method, we never look at a sleep problem in isolation. When a family comes to me with a baby or toddler who wakes between 4:30 and 6am, the sleep environment is one of the first things I check, alongside timing and feeding.
Here's how I think through early wake ups:
- Temperature. Is your child kicking off a blanket, or is the TOG too light for the room? A cold child in the early morning is one of the most overlooked causes.
- Light. Is early sunlight sneaking in around the curtains?
- Timing. Is bedtime too late or too early, or is the last wake window too long, so your child is overtired?
- Feeding. Is your baby genuinely hungry by morning because daytime feeds have become short "snacks"?
Fixing the blanket is often the quickest of these, which is why I always start there.
🔗 Why Is My Baby Waking Up Too Early? →
🔗 The Snacking Cycle: Is Daytime Feeding Affecting Your Baby's Night Sleep? →
When Should My Toddler Move to a Bed?
I recommend keeping your child in a crib until at least two and a half. Moving a toddler to a big bed too early is one of the most common causes of what I call a "jack-in-the-box sleeper": a toddler who pops out of bed again and again and can't settle independently.
The crib, plus a sleep sack, gives your toddler clear boundaries and keeps them warm. That combination does a lot of quiet work in preventing bedtime battles.
🔗 When Should I Move My Toddler Out of the Crib? →
🔗 Toddler Won't Stay in Bed? How to Help Your Toddler to Stay in Bed →
My Favorite Sleep Sack: Woolino
Of all the sleep sacks I recommend, Woolino consistently sits at the top of my list, and it comes down to the material.
Woolino's merino wool sleep sacks are naturally temperature regulating in a way synthetic fabrics simply can't match. Merino keeps your baby warm when the room is cool and releases heat when it warms up, so it handles those unpredictable shoulder seasons when the temperature swings overnight. It's also naturally moisture-wicking, pulling sweat away from your baby's skin instead of trapping it.
Woolino's universal sizing fits babies from around 2 months to 2 years, so you're not replacing sleep sacks every few months. It's a bigger upfront investment than a basic cotton sack, but for something your baby wears every single night, the quality and longevity are worth it.
Quick Summary
- No loose blankets in the crib for the first 12 months (AAP)
- Use a sleep sack from the newborn days on as the safe alternative
- Weighted sleep sacks or blankets are not recommended
- Choose your TOG based on room temperature, not just the season
- Pick breathable natural fibers like cotton or merino wool, and skip heavy synthetic fleece
- Even after 12 months, a sleep sack beats a blanket because they can't be kicked off
- Being cold in the early morning is a common, overlooked cause of early wake ups
- Keep your toddler in a crib until at least two and a half
What's in the Book
My #1 bestselling book The Helping Babies Sleep Method: The Art and Science of Teaching Your Baby to Sleep covers the sleep environment as part of a complete framework that connects sleep, feeding, timing, routines and how you respond to your child for babies up to 24 months. If early wake ups or night wakings are wearing you down, the book walks you through how to find the real cause.
Further Support for Your Child's Age
Whether you're in Palo Alto, San Jose, San Francisco or anywhere across the Peninsula and South Bay, or working with us virtually from anywhere in the country, we help families build safe, healthy sleep at every age.
🔗 Newborn Sleep Coaching: 0–3 Months →
🔗 Baby Sleep Coaching: 4–24 Months →
🔗 Toddler Sleep Coaching: 2–4 Years →
🌟🌟 More of a DIY er? Online Class 4 to 24 Months →
Or if you'd like to talk through your situation first, a discovery call is where we start. No pitch, no pressure.
🔗 Work With Us: Schedule an Intro Call →
Frequently Asked Questions
When can my baby sleep with a blanket?
The AAP recommends keeping loose blankets out of your baby's sleep space for at least the first 12 months. Even after that, a sleep sack is usually the safer and more practical choice, because it can't be kicked off during the night.
Why can't babies sleep with blankets?
In the first year, babies can kick or wriggle a blanket over their face but don't yet have the motor control to move it away. Loose bedding raises the risk of suffocation and strangulation, and is linked to a higher risk of SIDS.
What can I use instead of a blanket for my newborn?
A wearable blanket or sleep sack. It keeps your baby warm with nothing loose in the crib. In a cold room, add snug-fitting clothing underneath.
Is a sleep sack safe for a 6 month old?
Yes. Sleep sacks are safe from the newborn days on. Choose a TOG that matches your room temperature, make sure the neck and armholes fit snugly, and avoid weighted sleep sacks.
What TOG sleep sack do I need for winter?
For rooms between 61 and 68°F (16–20°C), a 2.5 TOG is a good fit. If your home stays above 69°F overnight, a 1.0 TOG may be enough even in winter.
Are weighted sleep sacks safe?
No. The AAP recommends against weighted sleep sacks, swaddles and blankets because they can put too much pressure on a baby's chest and lungs.
What fabric is best for a baby sleep sack?
Breathable natural fibers like 100% cotton or merino wool. They absorb moisture and pull sweat away from your baby's skin. Research on babies is limited, but newborns can't regulate their temperature well yet, so I recommend natural fibers and avoiding heavy synthetic fleece.
Can a 1-year-old sleep with a blanket?
Technically, yes. But I still recommend a sleep sack at 12 months, because toddlers kick blankets off overnight and wake up cold in the early morning.
Why does my baby wake up at 5am?
Early wake ups usually come down to temperature, light, timing or hunger. Body temperature naturally dips in the early morning, so a child who has kicked off a blanket can wake up cold. A sleep sack takes this variable away.
When can my toddler sleep with a pillow?
There's no rush. Pillows aren't needed in the crib, and most toddlers sleep comfortably without one. Pillows are designed to keep the spine neutral for side sleepers, or to gently support the head for back sleepers, and most toddlers don't need either. Many families wait until their child moves to a big-kid bed.
What is the safest sleep environment for a baby?
A firm, flat crib or bassinet with only a fitted sheet: no loose blankets, pillows, bumpers or positioners. Your baby goes down on their back, in a sleep sack, in a room that isn't too warm.
References and Further Reading
- American Academy of Pediatrics, HealthyChildren.org: How to Keep Your Sleeping Baby Safe: AAP Policy Explained
- American Academy of Pediatrics, HealthyChildren.org: Swaddling: Is It Safe for Your Baby? (Moon RY, Glassy D, 2022)
- Moon RY, Carlin RF, Hand I; AAP Task Force on SIDS. Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment. Pediatrics. 2022;150(1):e2022057990.
- Core body temperature and early morning waking (PubMed 39289281)
- Sarah Mitchell's book The Helping Babies Sleep Method: The Art and Science of Teaching Your Baby to Sleep provides the integrated framework connecting sleep, feeding, timing, routines and parental response used throughout this post.
- Chow CM, Shin M, Mahar TJ, Halaki M, Ireland A. The impact of sleepwear fiber type on sleep quality under warm ambient conditions. Nature and Science of Sleep. 2019;11:167–178.
- The Role of Brown Adipose Tissue and Energy Metabolism in Mammalian Thermoregulation during the Perinatal Period (review, PMC10339909)
This content is for educational purposes and does not replace medical advice. Always talk to your pediatrician about your child's sleep safety.
Read next:
- The Helping Babies Sleep Method: A Complete Overview
- Swaddling Guidelines: When to Start, When to Stop
- Why Is My Baby Waking Up Too Early?
- Night Wakings by Age: What's Normal and What Needs Support
- Toddler Bedtime Battles: How to Create Calm, Consistent Evenings
- How to Dress Your Baby for Winter Sleep
- Baby Sleep Environment Checklist: How to Create an Ideal Space
