If you've gotten this far, I hope you know how to answer this kind of question: be affirmative and supportive without damaging your credibility, all while helping to steer clear of the overalls.
According to a frightening article in New York Magazine (is there ever any other kind?), pregnant New Yorkers are increasingly pressuring themselves--and each other--not to gain weight (i.e., too much? an ounce more than absolutely necessary? an ounce more than that size-2 at work, the tramp? as much as Kate Hudson? WTF??) during pregnancy.
What does this translate into on the ground? Spot weightcheck on UrbanBaby's anonymous message boards; impossible-to-get-into pregnancy pilates classes; women lying about how far along they are; and morning sickness envy (it gives them an excuse for vomiting). One mom-to-be gets right to the heart of it: "I really don't want this pregnancy to change my life." [I'm sure it won't. Hasn't changed ours any.]
Seriously, they should pack up all these crazies and put them on an island somewhere. [Oh. Waitaminnit. They DID.]