I thing if you stick with her real name, others should catch on. For those who don't, a simple, "oh, her name is Abigail" should suffice. I have a four syllable name and growing up my mom always called me by my name, so going to school, when others would try to shorten my name, I'd just correct them (and maybe not too politely, but that was a long time ago).
I just shortened my name on here because I have yet to tell my friends (just family knows) and some of these friends are pregnant, too. I'm going to tell them soon, so now I guess I'll just sign my real name...
Juliana (Jules-a nickname from MIL, but I love it!)