There are rules about what you can and cannot ask women. Well, technically you can ask a woman anything. Just keep in mind that what you ask and how you ask it is telling of your upbringing and your level of couthe.
Back in the day the basic no-no's were you never asked a woman's age or her weight. Today those no-no's still exist, but it has expanded to topics like: Is her hair is really hers? (btw we're talking the hair on her head or eyelashes) Does she get botox? Are her boobs real? Is that an Adam's Apple? You guys feel me. You can assume the hell out of someone, but it is TACKY TACKY TACKY to actually vocalize it.
Now, especially considering my current state of being I think it goes without saying that you NEVER E.V.E.R. ask a woman when she's due- 'cause just like you never know what's really going on in someone else's relationship you NEVER know what's going on under someone's shirt.
That is because:
a) some women just have bloated days every now and then (Hello! Been there done that!)
b) some women are skinny, but happen to have "bird bodies" as my great-uncle used to say
c) some women have 1 major "problem area" and it happens to be their belly
d) some women are just overweight and you can't tell period
e) some women have already had a baby and just not bounced back yet- or ever
So the general rule of thumb is: Unless you actually see a head crowning from a vagina you say NOTHING unless something is said to you. Which leads me to believe or at least want to believe that's why so few people have offered me their seat on a crowded subway in NYC. That may be my Texas "Pollyanna" side coming out, but I'd like to think they're not being cold callous New Yorkers, they just don't want to offend me in case I'm having a "fat day." 'Cause I'll be real, even at 8 months prego I still have days where I look less pregnant and more like I just REALLY like bread. Yes, it's a blessing and curse.