I grew up in Fort Worth, and actually first heard the phrase in my baptist church, much to the delight of the older ladies making a fuss over a mama-to-be. I’m 46 now and in all my years, NEVER come across someone who found the phrase ‘vulgar’, and I’ve lived all over the north Texas area and northern California area—your mileage may vary, though, depending on your region and religion, I guess! [shrugs]
Not sure if you’ve been around a pregnant person before, but when the belly starts stretching (as mine is doing at this very moment) a bump (generally called the baby bump, not just ‘bump’ in most cases, although I knew a woman who called hers “The Bump” before she knew the gender affectionately) indeed does form—a living bump with a beautiful heartbeat (in my case, 2 beautiful heartbeats :*) that is now moving on it’s own when one of the babies kicks/punches inside. :*) One of the most wonderful, glorious feelings I’ve ever felt in my entire life!! :*) Not a single thing ‘vulgar’ about it, IMO.
Regardless of whether you have heard anyone use the term vulgar, one of the definitions of vulgar is, “lacking refinement;” another is “of ordinary people’s language” and, indeed, the term “baby bump” is vulgar by that definition. I have been around plenty of pregnant women and myself was one some 32 years ago and, no, that term was never used. I don’t know about “Texas,” or North Carolina, but, trust me, religion has nothing to do with it.
I have noticed that the past several years have shown an increasing decline in manners, specifically in regards to the use of language. There is much in our language that, while not directly profane, is very vulgar. I admit I have occasionally uttered words that years ago would have been very improper for a lady to say (e.g. the word(s) crap or crappy as in “I had a crappy day”) and remember being chastised for saying that word.
I try to stay classy and have my own struggles, so I definitely won’t be adding “baby bump” to my vocabulary.
Oh, I almost forgot - congrats on your two little ones - blessings to you all.