A pregnancy announcement is a huge deal. It signifies that someone's family is going to be expanding, and there are definitely emotions at play for all involved. But no matter how you feel about someone's pregnancy, especially when that someone is not you, you shouldn't say any of these stupid things to them when they tell you the big news.
And, yes, having had four children, I've heard many of these, especially when I got to pregnancy three and four. A simple congrats? Perfect. Questions about the due date or where the baby will be born? Wonderful. These things? Just no.