Newborns sleep best in a fitted one-piece sleeper or a bodysuit paired with a wearable blanket, with no loose blankets in the crib. The exact combination depends on your nursery temperature, but the goal is always the same: keep your baby warm enough to sleep comfortably without any risk of overheating or suffocation from loose bedding.
The Safest Sleepwear Options
For most newborns, nighttime clothing falls into one of three categories: footed sleepers (also called footie pajamas), a bodysuit or onesie worn under a swaddle, or a bodysuit layered with a sleep sack. All three keep your baby covered without introducing anything loose into the crib. The American Academy of Pediatrics is clear that loose blankets, pillows, stuffed toys, and bumpers should stay out of the sleep space entirely.
A footed sleeper with a zipper is the simplest option, especially for middle-of-the-night diaper changes. If the room runs cool, you can add a sleep sack over it. A sleep sack is essentially a wearable blanket: a zippered pouch that covers the torso and legs while leaving the arms free. It gives your baby warmth without the hazards of a traditional blanket.
For the first weeks of life, many parents prefer swaddling. A snug swaddle mimics the feeling of the womb and can reduce the startle reflex that wakes newborns. You can use a purpose-built swaddle wrap with velcro tabs, which is easier to get right than a traditional swaddle blanket. Underneath, a simple short-sleeve or long-sleeve bodysuit is usually enough.
When to Stop Swaddling
Swaddling has an expiration date. The AAP recommends weaning off the swaddle as soon as your baby shows signs of trying to roll over, and many babies start working on rolling at around 2 months of age. If a swaddled baby rolls onto their stomach, they may not be able to push back over with their arms confined, which creates a suffocation risk. Once rolling starts, there’s no going back to swaddling. At that point, switch to a sleep sack that leaves arms completely free.
Choosing Layers by Room Temperature
The recommended nursery temperature for babies is 68 to 72°F (20 to 22°C). A good rule of thumb: dress your baby roughly the way you’d dress yourself for sleep, plus one light layer. In a room at 70°F, that typically means a long-sleeve bodysuit under a medium-weight sleep sack. In a warmer room, a short-sleeve bodysuit alone or with a lightweight sleep sack may be plenty.
If you buy sleep sacks, you’ll notice they come with a TOG rating, which measures how much heat the fabric traps. Higher TOG means warmer. Here’s how to match the rating to your nursery:
- Above 80°F (27°C): 0.2 TOG, the thinnest option, essentially a single layer of muslin
- 73 to 79°F (23 to 26°C): 0.5 TOG, lightweight for warm rooms or summer
- 68 to 73°F (21 to 23°C): 1.0 TOG, the most common year-round weight
- 61 to 68°F (16 to 20°C): 2.5 TOG, a heavier option for cooler homes in winter
- Below 60°F (16°C): 3.5 TOG, the warmest available
Most homes with central heating or cooling will sit in the 1.0 TOG range. If you’re unsure, start lighter and check your baby after 15 to 20 minutes. It’s easier to add a layer than to catch overheating after the fact.
Best Fabrics for Newborn Sleepwear
Cotton and bamboo are the two most popular choices, and both outperform synthetics. Synthetic fabrics can trap heat and moisture against the skin, leading to irritation and discomfort. Natural fibers breathe better and help regulate temperature on their own.
Organic cotton is durable, easy to wash, and breathable in all seasons. It holds its shape through countless washes, which matters when you’re doing laundry constantly. Bamboo fabric is silkier and slightly better at wicking moisture away from the skin, making it a strong pick for babies who run warm or sweat during sleep. Bamboo is also naturally hypoallergenic, so it tends to be gentler on babies with eczema or sensitive skin. Either fabric works well. If your baby’s skin is easily irritated, bamboo has a slight edge. If you want something low-maintenance that dries quickly, cotton is hard to beat.
What Not to Put on a Sleeping Newborn
Skip hats indoors. Newborns regulate a significant amount of body heat through their heads, and a hat in a warm room can cause overheating quickly. Hats are fine outdoors or in the first hours after birth in the hospital, but they don’t belong in the crib at home.
Avoid anything with hoods, drawstrings, or loose ties that could bunch around the face or neck. Mittens are generally unnecessary for sleep. If you’re worried about scratching, look for sleepers with fold-over cuffs built into the sleeves. And again, no loose blankets, no matter how thin. A sleep sack does the same job without the risk.
How to Tell if Your Baby Is Too Warm
The quickest check is to touch the back of your baby’s neck or their chest. These spots give a more accurate read on core temperature than hands or feet, which tend to run cool in newborns regardless. If the skin there feels hot or damp, your baby is overdressed.
Other signs of overheating include flushed or red skin, damp hair, fussiness or restlessness, and unusual sluggishness. Some overheated babies sweat visibly, but others don’t, so you can’t rely on sweat alone. A heat rash, tiny red bumps that cluster in skin folds around the neck and diaper area, is another common signal that your baby has been too warm.
Overheating is more than just a comfort issue. It’s an independent risk factor for sudden infant death syndrome (SIDS), which is why getting sleepwear right matters beyond just helping your baby sleep well. When in doubt, go with one fewer layer rather than one more. A slightly cool baby will fuss and let you know. An overheated baby may not.