How did Bella almost die in Breaking Dawn?

Bella almost dies in Breaking Dawn because when Edward and Bella go on there Honeymoon they have sex, and after 2 weeks on holiday Bella finds out she is pregnant, then the baby is developing at a rapid pace to quick for normal, so they call Carlisle to let him know and Carlisle orders them to come home quickly, when Carlisle examines Bella, they are told the baby is half vampire and half human, after a month of pregnancy, Bella stomach is the size of someone who has been pregnant for nine months, so Carlisle has to get Bella to give birth other wise Bella will die and so will the baby, so as Bella is giving birth, the baby breaks almost every bone it passes and Bella looses loads of blood, so to save her Edward has to inject venom it to her heart to make her turn into a vampire quicker, after that the baby is fine and Bella is fine because she is a vampire and they live almost happily ever after.....