My bestie is a little over a month pregnant and has a bit of a bump already. It's really weird because she knows it's not the baby, but she's gaining weight anyway (in spite watching her calories meticulously). She's always been slender, so this weight gain really bugged her.  She went to her OB and she told her it's normal for some women to get extremely bloated, and even a little water weight shows a lot on a slender frame like hers.  I could see how some really dumb people would think something like that (or just straight up fat) is an actual baby bump.