Umm duh! First of all ur putting all those cancer causing chemicals into your body..and guess what, that means it gets in ur breast milk too. You're baby has to drink that. And also there's the whole second hand smoke thing. Just cuz you walk off to go smoke doesnt mean that ur baby isnt exposed to it. Smokers can't smell themselves so they don't know it, but ur covered in that crap and ur baby is breathing it in. Long story short, i'm guessing u love ur baby more than ur ciggs. So drop the ciggs before they hurt the baby. (cancer is getting more and more common, this could have long term effects on ur kids life when they're an adult. just sayin...)
It can't be good. What if you ash on the baby's head? I'm kidding about that but I don't know why you would consider it. You managed to quit while you were pregnant, right? You shouldn't start back up again. I don't know the health effects of it, but I bet you can find plenty on the subject online.