I wouldn't just because if for some reason they test your or the baby and you smoked late in pregnancy, it would show up. I don't oppose smoking weed but I wouldn't just because I had a m/s last year and I smoked to make myself eat, don't think they were related by any means, just makes me paranoid. lol
I ate spearmints to control my nausea, or talk to your doctor and they should give you meds for it, mine gave me some, never ended up having to take them, long story.