Hi there
I just had exactly this conversation with my ob. I have had cold sores in the past, and was concerned about how to manage one if one decided to rear its ugly head during preg!
He said exactly what Leasha said - as long as you use it sparingly and topically only then the risk is practically nothing. It would be such a trace amount that it would do no harm.
I worked myself up a bit reading all sorts of nasty things on the internet saying not to use it, but I decided to trust my dr. I have tried other more 'natural' remedies and they have never helped to relieve them. Although, a daily dosage of L-Lysine has kept them at bay in the past. I have read that it is safe to take during preg, but again, I'd check with your trusted dr.
Hope that helps.