The rides that are fast or bumpy are not recommended for pregnant women. The Guidebook for Guests With Disabilities is available at Guest Services at each of the parks. It will have a list of which rides are not recommended. You can also ask the CM at the entrance if the ride is safe. Here is a link to the DIS Disabilities Info Main Page.
You can also get more informaiton from the FAQ - just click on the link in my signature.
When you get to the parks, you will find that the park maps also have a code on them that tells which are not recommended. They will be marked with a red triangle. You will also find signs at the entrance and before boarding rides that have recommendations against riding for some reason. âÂÂ