In and of itself, pregnancy can run the gamut from "pleasant challenge" to "Hell on Earth that must be endured for the better part of a year." No matter how it shakes out, it requires some degree of mental and physical fortitude that (most) pregnant woman don't have to spare. Often the hardest part about being pregnant? Other people. While they can say and do some profoundly dumb or thoughtless crap, some of the cruelest things anyone could do to a pregnant woman are completely unintentional. The thoughtless person in question may, in fact, be completely unaware they're being thoughtless at all.
On the one hand I think people should be given the benefit of the doubt. Like, they've never been pregnant before (if they were it was a while ago, or maybe they had one of those magical pregnancies where they didn't have the same issues someone else is experiencing on the regular), so they probably don't know why what they've said or done is a problem. Other times, however, they're just being really obnoxious and should absolutely know better. In either scenario, I think everyone can stand to take a little more time and think before they act (or speak). Actually, that's a good life rule, right?
Here are some of the things you might want to think twice about, before doing to a pregnant woman. Make no mistake, she will remember this cruel scorn (or, ya know, flippant rudeness) for years to come.