I was having some problems with getting a page loaded to reply.
While some of the posters might have been a bit short in their comments, pregnancy is not a disability and most pregnant women don't need any special assistance.
It is true to WDW recommends a wheelchair or
ECV for guests who are concerned about their ability to stand in lines. The reason for this recommendation is that the time spent walking or standing in line is just a small portion of the day at WDW. Someone who is concerned about the lines is going to have problems in many other places to.
A GAC does not really help with issues with standing that much because there are very few attractions that have any place to sit. So, if you need a place to sit in line, the only way to guarantee to have one is to bring it with you by using a wheelchair or ECV.
(there is a post on page 2 of thedisABILITIES FAQs thread that lists attractions that involve stAnding for all guests unless they have a wheelchair or ECV.
If sitting in a wheelchair made the OP motion sick, she may want to try an ECV. Motion sickness can result from looking in a different direction than a wheelchair is going. Since the driver of an ECV needs to look where they are going, motion sickness is much less likely.
GACs are also not used for most character greetings. You may be able to get some assistance from the CM at the greeting entrance, but lot depends on what is available (there are often no seats nearby) and it also depends on staffing (there are usually very few CMs at the character greetings)
As several posters mentioned, character meals are one way to avoid waiting in line. The characters in the Town Square Theater at MK DO have Fastpasses. The characters there include the Princesses and Mickey Mouse (sometimes joined by Minnie).
If you have a smartphone, there are many helpful apps that include estimates of waiting times for each attraction. If you have Verizon cell service, you can get Mobil Magic, which is the official Disney app and is actually tied in to the WDW system. It's not available, at least now, or iPhones.
Other popular apps are from
undercover tourist and touring plans.com
Both of those companies also have helpful information on their websites. Just knowing which park is their 'recommended park' for the y will help ou a lot with avoiding waits.