weed and breastfeeding

I've seen many posts about women smoking weed while pregnant. some people are for it and others are against. but I have yet to really see the opinions about women smoking pot - occasionally - while breastfeeding. what is your take on this? (I've done my own research and there isn't enough evidence out there because nobody truly wants to make this into a study. women aren't willing to put themselves and their babies through it.) should women be worried about their babies future and health while smoking once a week or a couple times a month?? or is it harmless and okay?