If mucus in stools was the only symptom of something wrong... what would you do?

DD2 is almost 3 weeks old and has been having mucus in her stools the past week or so. Her stools aren't green so it is really just the mucus. I am wondering what to do about the it. Is it just normal for her or is it a sign of an intolerance of some sort? DD2 is my 3rd LO but I haven't had any problems with any sensitivity to foods with either of my other LOs and I don't really know where to go from here. Call the pediatrician? Lactation consultant? Any advice???