Fright fest, to go or not to go?

Meagan
My husband and I work with high school kids and are supposed to take 15 kids to six flags for the fright fest this weekend. I have a doctors appointment where I'll ask tomorrow but im just worried about the 10 hour drive on a bus and the scare factor. I've been reading that you shouldn't go to haunted houses while pregnant and I'm not sure why. Im 9 weeks along and I want to protect the baby. Advice?