In addition to roller coasters, there are a few other rides at the amusement park that pose the same risks for pregnant people. You should also steer clear of pendulum rides, free-fall rides, swing rides, spinning rides (including the teacups), bumper cars, and water slides.
In general, the rule of thumb for pregnancy and Disney World rides is height restrictions. Any ride with a height restriction (of any height) is not recommended for pregnant people, and you'll see signs notifying guests of these restrictions outside the entrance of these rides.
Even early in pregnancy, moms-to-be need to exercise a bit of discretion when it comes to rides. Although there isn't a scientific consensus that roller coasters and other high-speed rides are harmful during pregnancy, they haven't been proven completely safe, either.
That's right, there are attractions in Disney World that you can still ride while pregnant. Obviously, rides like Tower of Terror and Guardians of the Galaxy: Cosmic Rewind aren't included on that list.
After the first trimester, you can use hot tubs or saunas without posing any significant risks to your baby. Even then, you should be on the lookout for potential discomforts. If you feel your temperature rising too much, if you feel dizzy, or if to think you're going to faint, get out of the jacuzzi immediately.
The great thing about the Disney parks is that most of the rides are safe for expecting mothers. You can use fastpasses to help keep your wait times down, which will help keep you off your feet for extended periods of time.