I was in better shape when I was pregnant than ever before or sense in my life. Crazy as it sounds, I took private martial arts lessons my entire pregnancy. Obviously no throws after a certain point, but my ability to center my weight got so much better. We did flow drills, and bag work, and lots of stretching and lunges, etc. I was in close touch with my body and just followed my instincts in terms of when to stop doing certain things. We ended each session with a visualization / meditation. Toward the end, DD started riding really low, which caused me pain, but we still got together and did what I could every week until close to the end.

Warning anecdotal evidence ahead:

DD has an extremely high working memory!