Well, when the kids are born, Disney takes them to a top secret location, and they spend 3 years learning to sing Its a Small World in 37 different languages, then they stay in that attraction, with their feet glued to the floor, until they turn 18, at which point Disney takes them out of Small World, and sends them across the park to become Jungle Cruise Skippers ...
No, actually, they do have themed costumes in maternity sizes. Generally the women continue to work in their area. At some point, they may be placed on modified duty if they're having issues with standing up/etc.