Spit Up

My son just turned 4 months. He has been spitting up (sometimes dribble, most of the time forceful) for pretty much 4 months. Peds says he will grow out of it. He is still eating almost every 2 hours during the day. Sleeps well at night though. He has to wear a bib all day because he will spit after the feed as well.

We use the Dr. Brown bottles and we are fortifying my milk because he needs more calories. He is also using a preemie nipple. Any suggestions on something else we could do??