Breaking Dawn by Stephenie Meyer

Breaking Dawn is the fourth and final novel in the Twilight series by Stephenie Meyer. Divided into three parts, the first and third sections of Breaking Dawn are written from Bella Swan's perspective and the second is written from the perspective of Jacob Black.
Breaking Dawn was released on August 2, 2008 at midnight release parties in over 4,000 bookstores throughout the US. From its initial print run of 3.7 million copies, 1.3 million were sold in the first 24 hours of the book's release, setting a record in first-day sales performance for the Hachette Book Group USA.
Bella and Edward are married, but their honeymoon is cut short when Bella discovers that she is pregnant...
Bella's pregnancy progresses rapidly, severely weakening her. She nearly dies giving birth to her and Edward's half-vampire-half-human daughter, Renesmee, but Edward injects Bella with his venom to save her life and turns her into a vampire. A vampire from another coven sees Renesmee and mistakes her for an "immortal child". She informs the Volturi, as the existence of such beings violates vampire law. The Cullens gather vampire witnesses who can verify that Renesmee is not an immortal child. After an intense confrontation, the Cullens and their witnesses convince the Volturi that the child poses no danger to vampires or their secret, and they are left in peace by the Volturi. (Summary by Wikipedia)