You have probably noticed that your baby’s sleep surface, whether it’s a full-size crib mattress or a pad for a portable crib, is firm and may not seem comfortable to most adults. But this is the way it is meant to be! The mattress or the pad for the portable crib should be covered by only a fitted sheet. There should be no other padding added to the mattress in an attempt to make it more “comfortable”. Doing so can be very dangerous for your baby.
Why are soft surfaces so dangerous? Well, because if an infant lays on soft bedding or soft surfaces (such as an adult bed or couch) that surface may indent or conform to the shape of the baby’s head and increase the likelihood that the infant will breathe in his/her own exhaled breath (carbon dioxide). These surfaces also increase the risk of suffocation if the baby would become face down in the mattress, couch, or another soft surface.
To reduce the risk of suffocation, have your baby sleep on his/her back on a firm mattress.