Traveling from Fort wayne In to Missouri while 8 months pregnant?

My fiance is taking a trip in a couple weeks with her family to see other relatives in missouri…While I will not be attending the trip due to wor conflicts. This will be both of our first child and she will be 8 months pregnant…I am worried she will go into labor while on the trip and will be 8 hours away…She assures me everything will be fine.What advice can you provide me to help convince her not to take this trip??