With just three days to go before she goes on maternity leave, Posthipchick offers some instructive observations on the awkwardness, both physical and social, of teaching while pregnant:
It's very strange to have something so personal happening to you while constantly being watched and monitored by 100 people a day. Especially when the personal/professional line becomes blurred, as it is wont to do when your students see you running out of the room to puke, or go to the bathroom, or when your belly is slithering around as you are trying to teach. None of it feels inappropriate, ... but I really try to keep up a boundary with my students, and pregnancy sort of forces it down a bit more than I would have chosen.