Unitarity versus Renormalizability of Higher Derivative Gravity in 3D
  It has been suggested that new massive gravity with higher order terms in the curvature may be renormalizable and thus a candidate for renormalizable quantum gravity. We show that three-dimensional gravity that contains quadratic scalar curvature and Ricci tensor is renormalizable, but those theories with special relation between their coefficients including new massive gravity are not. 
Kenji Muneyuki and Nobuyoshi Ohta
hep-th gr-qc