A very normal process for a young baby, spitting up occurs because the muscle that keeps food contained in the stomach is not yet fully developed. Spitting up may be a sign of overfeeding if it happens frequently or in combination with vomiting. Burping a baby doesn’t decrease spitting up, and if you’re too insistent, it may even make it worse by increasing the pressure on Lucy’s belly.
Some babies spit up much more than others, and at the end of the spectrum are those who have what we call reflux, a condition in which the stomach muscles are so loose that they can’t keep food down. This initially causes spitting up and evolves into vomiting. But remember, the two are quite distinct. As a rule, spitup lands on your shoulder, and vomit lands on the floor.