Baby reacting to Soy lecithin for clogged ducts

Veronica

After my third round of mastitis, my dr suggested soy lecithin and vit c. I’m pretty desperate but since I started taking it, baby is spitting up a lot and it smells like vomit. She also has a bright red rash on her upper chest, and waking frequently at night. Has anyone else had this happen? What did you do?