from 1:01 in the Avengers Age of Ultron Trailer
Unless I'm sadly mistaken, these are forceps used to deliver babies. So this either means that someone is having a baby (maybe Ultron is?) in the new movie, or moviemakers like to scare us with forceps assuming we wont recognize them as other than creepy looking medical devices.
The IT-0 Interrogation droid from Star Wars: A New Hope (the one that floated in to stick Leia with a "British Made" needle also sported a set of these forceps, along with other accouterments