I have found that new babies sleep better in a bodysuit and a bundler than in two-pieces. I recommend a baby is not put in a two-piece outfit for any sleep before 18 months of age. Bundlers are great for new babies, you don’t need to worry about doing up poppers or pulling their little feet in or out of the feet. To use a bundler you just fold it up under your baby to keep their feet in and warm, they are great for changing nappies in the night.