Fun fact about pregnancy: The hips can actually split apart where they join at the pubic bone starting in the 2nd or 3rd trimester. It's extremely painful for those it happens to and it is totally out of the control of the woman.

But yeah, go ahead. Tell women they can do whatever they want and set that expectation. My wife was devestated by her pregnancy and the feelings of helplessness it caused, despite trying to be active and eat well. She was ill from beginning to end and in pain for 80% of it.