Baby doctors (peds, fp), what is the thing you wish ob providers would tell their pregnant patients?

Wishes. Start with healthy habits now (no smoking, eat healthy, loose weight if you need to, exercise,) - you need to model the behaviors to keep your child healthy.
Choose peds b4 birth. Choosing and meeting a pediatrician before delivery really helps the parents thru "the next step" and decreases their anxiety making them both better parents and better patients:-).
GOOD NUTRITION. Good pre-natal nutrition is vital.