I don't have children and have never been pregnant but I absolutely get canker sores the most when it's about 2weeks before my period. Usually they're small, but once in a while I'll accidently bite/injure my lip and if it's around that time, it completely blows up into a big.painfil spot and I can't eat or speak properly. I'm current going thru one on about day 6 and most pain has subsided nit it's still a big raised bump and any additional injury can just make it worse. I'm also not on any birth control which helps, I think they used to be worse when I was on the pill.

I've noticed that staying hydrated and eating more "clean" or "whole" foods really helps, but mostly just not injuring myself and staying hydrated.