First of all, get the hand checked even though you think it's ok. Better safe than sorry while you are pregnant.
Now, if the aggression issues are just with food, then it's pretty easy to avoid the situations by completely separating them during feeding/treat times by putting them in different rooms or using an xpen. See if you can have a behaviorist come in to work with her.
Now, when the baby comes, it will be the same thing in reverse. It's time for the baby to eat, so the dogs get put up. No temptation equals less chance of biting.
Someone mentioned Sadie possibly being in heat, making her more aggressive. She's spayed, though, right? In any case, YOUR hormones can be giving off pheromones that may be upsetting her or she could be picking up on your tension. I found my dogs to be especially clingy and grumpy while I was pregnant, just like me
Good luck and get that hand checked!