In my first pregnancy I got lots, went to a wedding and had them on either side of the outside of my mouth. Super attractive! Or not. At the wedding, I met a midwife who reckoned Vitamin B intake was the key, ideally with fresh fruit and veg - tricky, because in that same pregnancy I really couldn't stomach anything even remotely green! So she reckoned Vegemite would probably help, and I guess it did, but I wasn't pregnant for much longer than that so I can't really say.

Saltwater gargle is a bit stingy, but can alleviate the symptoms. Oh, and plenty of rest. As if you're not exhausted enough