We have a family history of food allergies but none to nuts. So I ate peanut butter sandwiches all throughout my pregnancy with my first daughter and also breastfed her while eating peanut butter (I love that stuff). But, I found out my daughter is allergic to peanuts when she was 15 months old. Somebody watching her accidentally gave it to her and her face swelled up and she broke out in hives. Everywhere she goes she has to have her epi-pen with her. She is a class III out of V. It scares me to death so now with my son whos 9 months I didn't eat any peanuts during the pregnancy nor during BF right now. Actually I can't really eat it with my daughter around unless I'm not around her for 24 hrs(I don't know when thats going to happen) because she can get a reaction from me kissing her even hours after me eating it. So, if you don't have any family history of any food allergy I think its safe to eat it but if you do have it I would stay away from it until you are done BF