1) Get on it already.
2) What's the hold up? I want a grandkid/nephew/godchild.
3) I'm sure you won't have any problems (having a baby).
4) Are you pregnant yet?
I know that many people are simply excited for their friends to reproduce, but at any given moment, you do not know what hardship they are facing in that area. If I had been forced to leave my house for work just after the miscarriage and someone had asked me one of these questions, I probably would've given them the coldest shoulder I could muster in an attempt not to cry. Luckily, I work from home, so I didn't have to leave my house.
So, unless you are in the know, do not bring someone else's reproductive status up. I agree to show you grace if this happens in the future. And I hope other women do the same. But, just so you know, these are not things we want to hear.
If you are in the know, you're playing a different game. Pick your moments carefully and lob very soft pitches.
Can you think of any other things that should be on the DO NOT ASK list?