I usually don't do anything pregnant that I wouldn't do if I was holding a newborn. I don't feed a newborn beer in a bottle, therefore, even though many will tell you it is ok to drink 1 beer or glass of wine while pregnant, I still don't. I wouldn't take a newborn into a smoky restaurant or bar, therefore, I don't go in one while pregnant. I wouldn't take a newborn on EE, therfore, I wouldn't ride it while pregnant. I agree with your OB that it is very hard to MC if the baby and pregnancy are healthy, but you might not know there was a problem until after the ride......it comes down to- is a stupid thrill ride really worth it? You have a whole life ahead of you for that stuff and while parenting you will have to make much bigger sacrifices than just not riding EE, consider this good practice.