Hey - long-time lurker, first-time poster
When I was preg and visited Walt Disney World as well as Disney World, I had no trouble with nearly any of the rides. My mom is a midwife, so it was like having my own medic with me!
Buzz was NOT an issue. However, if you are prone to any morning (or afternoon, or evening sickness!), you may want to be cautious of the spinning rides. I had a couple of bad Mickey Bar + spinning = bad things incidences.
The rides I did NOT do were:
Any of the coasters
Tower of Terror
Mission Space
Kilimanjaro Safari

Teacups
Star tours
Dinosaur (or Indy at DL)
the little speedway or autotopia (Too bumpy)
Other than that, I think I was good.
Post baby: My LO has been on Pirates and the Safari ever since he was 8 months old! He loves Pirates b/c of the drop (securely wrapped in my baby wrap, of course) and thinks the Safari is awesome with all the animals. Of course, I must be driving ever other guest insane with my constant monologue of "Look Patrick, look, look, look!!".