I wouldn't touch it even if it were legal, but then again, I don't do ANY recreational drugs and find smoking in general to be unappealing.
That said, having endured 6+ months of miserable morning sickness with 4 pregnancies, I can understand the appeal of the anti-nausea properties of THC.
That said, I have indulged in things like sushi, lunch meat and reasonable amounts of caffiene during pregnancy. There's something about a mostly flat Cola drink that helps me through the nausea.
Next pregnancy i absolutely will if i have nausea like the last time. However i live where it is decriminalised so there is much less of a legal risk for me- as in a fine if i get caught with it.