Babies should sleep on their sides or stomach
A few decades ago, people believed you should make babies sleep on their sides or their stomach to prevent choking on spit-up. But babies may not be able to breathe well if they sleep on their stomach, and if they sleep on their sides they can roll over onto their stomach and have the same problem. In rare instances, this can be fatal. While sleeping on their backs, babies cough up or swallow anything they might spit-up, so it is, in fact, safer for them to sleep on their backs.