Contact terms occur in gravity when there are non-minimal interactions, ( M P l a n c k 2 + α α ϕ ϕ 2 ) R , or in Brans-Dicke Theory, ( M P l a n c k 2 + κ κ M P l a n c k Φ Φ ) R . The non-minimal couplings are quantum equivalent to an "Einstein frame," with a pure Einstein-Hilbert action, M P l a n c k 2 R , owing to gravitational contact terms. These arise classically from graviton exchange interactions. The contact terms are an essential, yet hidden, part of the action and, if they are ignored, the Feynman diagram loops in different frames yield different results. At the leading order in 1 / M P l a n c k 2 including the contact terms is equivalent to performing a Weyl Transformation to remove the non-minimal couplings and taking the theory to the Einstein-Hilbert form. In this sense, the Einstein-Hilbert form of the action is unique and "frame ambiguities" in loop calculations do not exist.