From what i understand Twilight is written by a crazy mormon lady who has some issues.
From what I've heard, in the last book the main chick gets pregnant by the vampire but the fetus is so strong it starts to kill her from the inside since its a super strong vampire fetus. So she becomes a vampire too so that she wont die. The baby is born but there is some complication so the vampire guy gives the chick a C section using his sharp vampire teeth. The werewolf guy falls in love with the baby. Like he "loves" loves it.
Personally I don't understand the vampire craze. I liked blade but all these new projects aren't for me, too sappy and bad plot. If thats what your into though then thats what your into, go with it.