According to Digital spy
The sex scene in Twilight: Breaking Dawn - Part 1 has been cut down so the movie can be given a 12A, it has been revealed.
The British Board of Film Classification advised producers to edit the "graphic sight of Edward thrusting while he lies on top of Bella" to avoid the film being given a 15 certificate.
"This film was originally shown to the BBFC in an unfinished version," a statement on the BBFC website says. "The BBFC advised the company that the film was likely to receive a '15' classification but that the requested '12A' certificate could be achieved by making changes to a sex scene between the Edward and Bella characters.
"In particular the BBFC suggested that [the] more graphic sight of Edward thrusting while he lies on top of Bella, and while her legs are wrapped around his torso, be removed.
"When the finished version of the film was submitted these changes had been made, with the scene having been reduced in length and with less focus on full body shots. As a result, the film was classified '12A'."