Hats and beanies are only safe when baby is awake.
When a baby is sleeping with a hat or beanie, they pose a risk of suffocation, strangulation and overheating.
A big concern parents have with newborns is that they will be cold.
To keep warm, your baby does not need their head covered.
Use sleeping bags for layers, and refer to TOG guides to get an idea of what baby should be wearing.
Check babies back or neck, and they should be warm, but not hot.