Here is a list of things you CAN say to a pregnant lady that will make her feel awesome:
1. Wow- you're all baby! The rest of your body looks so thin!
2. I wouldn't even know you were pregnant from the chest up!
3. You are so cute!!
(That last one is particularly effective when said by a total stranger to a pregnant lady who hasn't had makeup on in 5 days because of a killer sinus infection that's making her eyes swell up like she's a prize-fighter, and forcing her to mouth-breath because her nose is more congested than I-294 Northbound at 8:00am on a weekday)