I had a guy trying to hit on me as I stood behind the counter at my store, then I moved so he could see the belly and he said, "Wow, I knew you had to be pregnant, you just have such a sexy glow about you!" I just rolled my eyes and walked away, but I wanted to tell him, "Yeah, that sexy glow... it's called sweat!"
Re: S/O interesting compliments
That would kind of creep me out. I think there is more subtle way to tell a pg lady she looks beautiful.