Breaking Dawn (part 1)

 If you've not read the book/seen the movie you might not want to read this - SPOILER ALERT!

In my opinion the latest twilight movie (as well as the book itself of course) looks at the dilemma created by a situation were a perfect happy couple (the fact that they're both young and one of them is a vampire being just an extension to the storyline) have sex (in this case during the honeymoon), the girl gets pregnant and later they find out that only one can survive - mother OR baby.
The way it's dealt with in Breaking Dawn is that the husband (Edward Cullen) considers the foetus to be an 'It' rather than his son/daughter and essentially wants to get rid of it (an abortion more or less) because he doesn't want to lose the love of his life (Bella). Bella, feeling all materialistic now that she's pregnant, doesn't want to kill her baby (to her it is already her child and not just an 'It') - she'd rather die.

With the support of Rosalie, Bella stands her grounds and carries on with the pregnancy whilst everyone around her watches as she deteriorates in front of their. This of course is different as Bella is being crushed from the inside by a vampire/human hybrid that is incompatible with her human body - as you'd expect. Whereas in real life a maternal death might occur if there is a complication with the pregnancy or if the mother develops an illness (e.g. cancer) in which case she'd have to take medication that would kill the foetus (or not take the medication and die). The case is often that the woman chooses the child's life over her own and this often created a problem in the family as they (the husband etc) will want HER to live rather than a foetus which has the potential to be a person. Often they will dehumanise the child in a way by referring to the baby as an 'It' - like Edward does. It's not that they're heartless, but nobody wants to lose a loved one. If they're newly weds the husband may also feel he can't look after a child on his own, nor would he want to - there is also the problem of what if he can't love the baby because it killed the love of his life? 

In Breaking Dawn Edward also doesn't want to lose Bella since he's only just married her, nor does he want to spend forever alone - hence why he tells Jacob to kill him if Bella dies. Jacob also considers killed the baby when they all think Bella is dead because he loved her.

However, when Jacob sees the child he imprinted on her. This of course is just the work of fiction and ties in with the whole theme of fate (the reason Jacob and Bella couldn't get together was so that he'd be able to imprint on her daughter who otherwise wouldn't have been born, Bella had to stand her ground and have the baby, Jacob had to imprint on Renesmee so that in the future he'd be able to protect her family from the other Quiluete wolves, etc), but it also suggests that when the baby is born everyone will fall in love with her - because how could you not.

Of course at the end of the movie (half way through the book more or less) Bella - almost miraculously - survives/comes back to life (which ever way you want to look at it). And as Stephenie Meyers said, the imprinting of Jacob on Renesmee is "the magic of setting things right—which doesn't happen in the real world, which is absolutely fantasy."