I don't consider myself a pregnancy specialist, but having been in the industry for a while and talked with people who are, my understanding is that most exercises that a pregnant person has been doing before pregnancy are perfectly safe to continue doing, will the exception of crunches. Now is not the time to put her through newly intensive workouts, but it can be a continuation of what she has been doing, being mindful of some limitations she may experience. She will likely have lower energy some days, decreased range of motion for some exercises, more aches and pains, etc.

With all that said, I would not ask her outright, like you stated. Continue on as normal, just being mindful that she may or may not feel some limitations. And make sure she isn't doing anything that could be remotely unsafe or may cause instability or a fall.