Im pregnant now 17.4 weeks today i stopped as soon as i found out i was about 6 weeks smoking before i found out.I told the doctor he didnt think it was a big deal as he told me there is no proof of birth defects from pot its tobacco thats worse.It was hard as hell for me to give up and still is hard but why risk hurting the baby.I was the same with my first son but i was more like 12 weeks preg before i found out he is ok but i think its best to give up while pregnant or breastfeeding.