I feel dumb for posting this but here goes lol. I was breast feeding at first but stopped and while breast feeding I began using bottles that were similar to moms breast and supposedly helps keep air out. Now that I am not breast feeding any more and my daughter is 5 weeks I have 9 "regular" bottles that I would like to use but worry that they will cause some type of irritant to her or perhaps have too much air in them. Here is a pic of them.