I’m reading this post too late to pass this along to the original poster, but I wanted to chime in in case anyone else is headed to WDW while pregnant.
We went for Memorial Day 2003 when my wife was at the beginning of her second trimester with our twin daughters. Her doctor told her to make sure to drink plenty of beverages. She drank alot of milk and fruit juices, but apparently those drinks don’t take the place of water.
Long story short, when we returned she was found to be dehydrated and her cervix was prematurely softening so she had to go on modified bedrest for the duration.
Moral of the story, especially if you’re from up north like us, you probably won’t realize how much the heat dehydrates you (especially the heat we just experienced down there last week).
Please, please please, just carry a water bottle at all times and sip as you go.