Does anyone have any good information on this? It sounds silly and weird. No, that’s not a bump. A mosquito bite makes a bump, being pregnant makes your entire abdomen swell enormously.
However, if you read pregnancy magazines, this terminology is used throughout them and it is used almost exclusively. So, not only did it change, but it changed very quickly and thoroughly.
I first heard it a few years ago with regard to speculating on whether certain celebrities were pregnant (“is that a bump we see?”). Maybe in my wife’s Glamour when I was sitting on the can. Clearly originated to refer only to when someone was just starting to show.
I think I first saw it in 2004 or 2005. I guess I could look this up–it was in a magazine like US, and the bump referred to was Gwyneth Paltrow’s first pregnancy.
If it was nonexistent in 2007, that’s a GOOD thing, maybe meaning its use is on the decline.
If you look at the phrases it’s referring to, they have nothing to do with pregnancy. It’s all stuff like “Did baby bump its little head?” The first one on that list that fits is from 1986, (at least, it looks like it fits from just the snippet):
I suspect it’s related to the attempted tightening of freedoms and morals. Previous to the Sixties, it was practically swearing to say that someone was pregnant. They were expecting.