Either way the baby had to come out, dead or alive. She was bleeding internally and wasn't dilated so c-section was the only option. Maggie cut her open with a dirty, bloodcrusted knife, with no medical training to guide her, so I imagine the incision was imprecise and messy. Not to mention the enormous amount of blood loss they had no way of replacing in the moment, and no tools to sew her back up again. All this being done in a non-sterile environment littered with risk of infection.
I just can't see how they could've chosen to save Lori over the baby. Given the circumstances, the only life they could save was the baby.
In terms of time, I would assume with lots of blood loss, one can die pretty quickly.
If in fact she is dead, which has to be the only realistic scenerio, I'd wish the writers would give us definitive closure to her death. That bloated Zombie could not have eaten all of Lori's remains. But if somehow she is still alive, that would be ridiculous as well. How could Carol save her with no tools to sew her back up and no means to replace all the blood loss?
Ah well. Guess just have to wait and see.