I have traveled to Disney in a number of different fashions. First as a small child, as a teen, as a young adult, as a mom, as a honeymooner and 8.5 months pregnant!
I would have to say that traveling to Disney while pregnant was the most interesting. If you are considering it, I would definitely say to go for it. (I would never suggest you don't go to Disney) :) But there are some things to consider.
First of all make sure that you have comfortable shoes! I wore my tennis shoes and my feet still HURT and they swelled up when they hadn't even showed signs of swelling yet. Disney's heat is what made my swelling begin, it never stopped from there and I could no longer wear my rings after the trip. Don't just stop at comfortable shoes! Make sure you take plenty of comfortable clothes too!
Also, make sure to drink lots of water! This is a no-brainer. You're pregnant and you need water. It is hot in Florida and you need more water. Stay hydrated!
Don't try to do it all and TAKE BREAKS! You will hear from people when you tell them that you are going to Disney while pregnant that you "won't be able to ride anything!" This is not true. There is still plenty to enjoy in the world! With that being said, make sure you check all the restrictions of the rides before riding. But of course there is still plenty to do! When we went we did a lot of shows and other things that we had never done before even after all the trips that we had to Disney. Take a little dip in the pool or explore the water parks! Slow down and enjoy your trip! Before long you will be pushing a stroller at Disney!
Most importantly make sure to talk to your Doctor before going! It is important that they approve your trip.
It is also important to note that if you are planning a Disney Cruise, you will not be allowed to cruise after your 24th week. You will still need a note from your healthcare provider before sailing before your 24th week. If you are able to take a Disney cruise while pregnant, DO IT! They are so relaxing and I can't think of a better way to pamper yourself while pregnant!
Overall, a Disney World trip while pregnant is just as great as any other Disney trip!