She goes into labor when she's on her way to the bathroom with Rosalie support when she drops her cup of blood on the ground and tries to pick it up regardless of Edward,Jacob, Rose, and Alice all being much faster than she is. Jacob hears a muffled crack from her mid section which was the placenta detaching. she is rushed into a upstairs room and placed on a operating table. Alice puts a blue-tooth in Rose's ear so she can follow Carlisle's instructions since he, Esme, and Emmet are out hunting. when rose starts to cut Bella's belly open to preform a Cesarean section the smell of the blood gets to her and Jacob and Alice have to wrestle her out of the room but she doesn't put up a fight due to her wanting to save the baby. Jacob goes back in and Edward finishes the cut and as Jacob is pumping Bella's weakening heart and starts to use his teeth to penetrate the vampire skin like membrane of the placenta and get Renesmee out. Bella gets to hold her for a second until she bites Bella's tit and Edward takes her back and scolds her. then with Jacob still doing compressions Edward give a under control rose Renesmee and break 1 of Jacob's fingers to inject his venom into Bella's heart with a syringe like doctors do adrenaline when a patient is dying. then he goes up and down both of her arms and bites and licks as much surface area as he can with his spit sealing the venom in. jacob loses hope and edward breaks another 2 fingers when he knocks jakes hand aside and takes over maddingly doing compresstions to get the venom through out her circulatory system. jacob walks downstairs in a "fog" and almost fazes and kill Remesemee when she looks into his eyes and he imprents on her. then of he off handedly hears bella's heart go into overdrive as the venom began to take affect. then comes a whole chapter about how the morphine makes her unable to move or scream like her body was made out of lead and gradually she regains control as it wears of but she still doesnt move to make the transmorfation easier on edward and eventually her heart speed up as the last of the venom dies away and her heart gives on last febble beat and stops for ever. then she wakes up and starts her life as a well controlled vampire newborn and as a mother. NOTE: she does lose control when Jacob calls Remesmee Nessie because her name is a mouthfull.
sorry if it was a little long but i didnt want to miss anything.