I'm pregnant with number 2 (13 weeks today - sooo happy to be out of first trimester!). Haven't been diagnosed with GD yet but as I had it last time round, I am doing low GI diet and linking in with diabetes nurse soon.
Anyway, googling this while I'm supposed to be working I found this really good review article that cites research that suggests things like Vit D and probiotics might have a preventative effect (alongside low GI diet and exercise). I had never heard of this before so thought I'd post a link here in case anyone else might find it helpful/useful/interesting/good form of procrastination:
www.ncbi.nlm.nih.gov/pmc/articles/PMC4360421/
probably no harm to run probiotics in pregnancy past gp I suppose, though can't imagine there being any problem with that ...
Anyway, good luck to any GD ladies out there. It does come to an end I promise 