Level 1: Reasons for babies spitting up milk: 1. Immature digestion: The digestion of newborns is not mature enough, and they are prone to nausea, vomiting, etc. Especially in the first few weeks after birth, babies are prone to spitting up milk because their gastrointestinal tract functions are not yet fully developed. 2. Incorrect eating method If the baby\’s posture is incorrect when eating or the sucking force is too strong, it will also cause