M.H.
My oldest never spit-up. My youngest would spit up anytime I nursed her and put her down before burping her--which happens when you have other stuff to deal with! She never seemed bothered by it, and once she started gaining weight, it never slowed. It usually goes away once they start sitting up. You can try holding the baby upright for 15 minutes after nursing to allow all of the milk to settle while the bubbles rise to the top--can help to lessen the spitting-up, but doesn't work for every baby.