I am not sure why, but this topic has been a concern of mine from the beginning! How do you keep baby warm when you can’t place blankets over them when they sleep? I know the optimal room temperature is supposed to be kept at an optimal 70-72 degrees for SIDS prevention, but just a cotton onesie during the dead of winter doesn’t seem like enough. Especially as the room cools throughout the night. If babies are supposed to be dressed in one layer more than you are and I sleep under a down blanket what is the equivalent for them?
We found two types of products that worked well for us, both at different stages of his growth.
As a tiny newborn we’d dress him in a onesie and then swaddle him. The swaddle blanket was thick enough to provide enough warmth. We also had him wear a little hat for the first few weeks when he slept. (he was born in December, so use your own judgement for your child based on the weather/temperature where you live).
Then during the next few months (1-3) we preferred to use a footed fleece sleeper. This you can put over a onesie or just by itself. If it was a colder I’d put over a onesie, if not then just by itself. This was great until Archer was a few weeks shy of 3 months old. You can also swaddle in a fleece sleeper, but I’d use a light swaddle as the sleeper is already warm. (As a reminder, you should only swaddle until 2 months old).
Once he began to move around more the 0-3 footed sleeper was getting tighter and because it’s micro fleece it doesn’t stretch. He simply outgrew this so we moved to the next item… the sleep sack! We loved the sleep sack. We would dress Archer in a cotton footed onesie and then put the sleep sack of that. It was warm and gave him freedom to move about. At this point he wasn’t being swaddled so he needed movement. Size small fits babies 10-18 lbs. It was also great in that if he diaper leaked, we had two layers of protection before it hit the mattress sheet. The issue with sleep sacks is they should only be used until the baby is 6 months old — according to physical therapists it’s not good to inhibit their leg movement even slightly, which the sleep sack might do. After 6 months it’s best to transition back to a footed fleece sleeper or just use a cotton onesie if it’s warm enough in your home.
Now that it’s summer Archer just wears a traditional cotton footed PJ. When it gets cold again, we’ll have to get some bigger footed fleece sleepers… sad to say goodbye to the sleep sack… just one more thing he’s grown out of!