The majority of mature women (and I stress mature) - whatever their vices, be it cigarettes, alchohol, whatever at least try and most succeed in giving up their habit for the duration of the pregnancy and longer if they are breast feeding. I'm not sure if you planned this baby, but whether or not you did or didn't, it's your responsibility to ensure the best health possible - forget the pro-weed information - I think you are just looking for an excuse to continue smoking. We can all find propaganda to support our habits if we look hard enough.
I think that if you can't give it up for 9 months - you may have more serious issues - it's called "addiction".