Your baby should sleep on their back, on a firm and flat surface, with nothing else in the bassinet except a fitted sheet. Every sleep, every time, including naps. This single setup is the foundation of safe infant sleep, and it applies from the first night home through the entire time your baby uses a bassinet.
The Correct Sleep Position
Place your baby flat on their back for every sleep period. Not on their side, not on their stomach. Back sleeping is the single most effective way to reduce the risk of sudden infant death syndrome (SIDS), and it applies to both nighttime sleep and daytime naps. Some parents worry that a back-sleeping baby might choke on spit-up, but healthy infants have a natural reflex that clears their airway.
If your baby rolls onto their side or stomach on their own and can roll both ways independently, you don’t need to reposition them. But that milestone typically signals it’s time to move out of the bassinet and into a crib, since it means your baby is becoming mobile enough to push against the bassinet walls.
What Goes in the Bassinet
A fitted sheet. That’s it. The U.S. Consumer Product Safety Commission puts it simply: “Bare is best.” Many young babies can’t lift their heads to pull away from soft objects that block their airflow, so the following items should never be in the bassinet:
- Blankets or quilts of any kind, including weighted blankets
- Pillows or pillow-like objects
- Stuffed animals or soft toys
- Bumper pads or mesh liners
- Sleep positioners or wedges
- Weighted swaddles or weighted sleepers
- Loose sheets or mattress toppers
If you’re worried your baby will be cold without a blanket, the answer is better sleepwear, not bedding. More on that below.
Getting the Mattress Right
The bassinet mattress should be firm and flat, not angled or inclined. When you press your hand into it, it should spring back immediately rather than conforming to the shape of your hand. A simple at-home check: if you place a weight on the mattress and the surface sags enough to touch objects placed beside it, the mattress is too soft.
Use only the mattress that came with your bassinet. Aftermarket bassinet mattresses are now regulated under updated federal safety standards, but the safest approach is sticking with the original manufacturer’s mattress. It was designed to fit that specific bassinet snugly, with no gaps between the mattress edge and the bassinet wall. If you can fit more than two fingers between the mattress and the side, the fit isn’t tight enough.
Room Temperature and Dressing for Sleep
Keep the room between 68°F and 78°F. A good rule of thumb: if you’re comfortable in the room, your baby probably is too. A fan on low can help keep air circulating, which also has a protective effect against SIDS.
Instead of blankets, dress your baby in a wearable blanket or sleep sack layered over a onesie or pajamas. Sleep sacks use a TOG rating to indicate warmth, and matching the rating to your room temperature takes the guesswork out of dressing:
- 0.2 TOG: warm rooms, 75°F to 81°F
- 1.0 TOG: comfortable rooms, 68°F to 75°F
- 2.5 TOG: cooler rooms, 61°F to 68°F
Don’t layer multiple sleep sacks or swaddles together. Choose one appropriate garment and add lightweight clothing underneath if needed. Signs your baby is too hot include sweating, damp hair, flushed cheeks, or a chest that feels hot to the touch. If their hands and feet feel cool but their chest and back are warm, they’re fine. Cool extremities are normal in newborns.
Swaddling Safely
Swaddling can help calm a newborn, and it’s safe in a bassinet as long as you follow two rules: the swaddle should be snug around the arms but loose around the hips, and you must stop swaddling as soon as your baby shows any signs of trying to roll.
Those signs can appear as early as 8 weeks and include rocking their hips side to side, twisting one leg across their body, reaching with both arms to one side, or arching their spine when held upright. Some pediatric guidelines recommend stopping swaddling around 8 weeks regardless, since development isn’t always linear and a baby might surprise you. Once you stop swaddling, a sleep sack with arms free is the natural next step.
Where to Put the Bassinet
Keep the bassinet in your bedroom for at least the first six months. Room sharing (not bed sharing) reduces the risk of SIDS significantly. The bassinet should be within arm’s reach of your bed so you can easily check on and feed your baby without bringing them into your bed.
Position the bassinet away from windows, blinds with cords, curtains, and anything your baby could pull into the sleep space. Avoid placing it next to a heater or in direct sunlight, both of which can cause overheating.
Preventing a Flat Spot on the Head
Back sleeping is non-negotiable, but spending every sleep on the same spot can sometimes lead to a flat area on the back or side of your baby’s head. You can reduce this risk without compromising safe sleep. Alternate which end of the bassinet your baby’s head faces, switching every few days. Babies naturally turn their heads toward activity or light, so changing their orientation encourages them to rest on different parts of their skull.
During awake time, give your baby plenty of supervised tummy time to strengthen their neck and shoulder muscles. Hold them upright over your shoulder when cuddling. Minimize time spent in car seats, bouncers, and carriers when your baby isn’t traveling, since those surfaces also put pressure on the back of the head.
When to Move to a Crib
Most babies outgrow a bassinet between four and six months. The transition point depends on your specific bassinet’s weight limit (typically 15 to 20 pounds) and your baby’s physical development. Move your baby to a crib if they hit the weight limit, start rolling over, push up on their hands and knees, or begin pulling at the bassinet sides. Any of these milestones means they need a larger, more secure sleep space. All the same rules apply in a crib: back to sleep, firm mattress, fitted sheet only, nothing else inside.