Hi Jillian,
First of all, congratulations! I loved visiting Walt Disney World while I was pregnant, seeing all those happy children around just got me more excited about having my own!
Soarin is an attraction that has a gentle swaying motion, combined with other effects such was wind and scents to give you the feeling that you are really flying. While I wouldn't hesitate to ride it while pregnant, every situation is different and I think it would be best for you to discuss your specific condition with your doctor prior to your vacation.
You will notice that the more aggressive attractions have warnings posted at the entrance and throughout the queue, and it's probably best to skip them this time!
I will suggest that you make sure you drink lots of water to keep hydrated, and maybe give yourself a little pampering at one of the
Spas on property! A pregnancy massage or pedicure would be a nice treat for yourself.
Have a great time!