Babies? No way!
There is a height requirement, anyway. My older ds is .75 of an inch away from being tall enough to ride. He will definitely be tall enough to ride next time we go.
What we did was get a Fastpass, then have one parent go with dd. That first parent gets a baby swap, then the other parent gets to go with dd. In the meantime, the parent waiting with ds would ride Winnie The Pooh as many times as we could. Plus buy candy at the Pooh shop outside the exit. It was fun.
I've never been pregnant, so I have no advice for the OP.