Ischemic placental disease can lead to hypoxia and abnormal pregnancy outcomes. R2* mapping using MRI can characterize placental hypoxia. However, conventional Cartesian MRI requires breath-holding which limits volumetric coverage, resolution, and signal-to-noise ratio. In addition, little is known about the nominal range of placental R2* at 3T and during early gestation. Therefore, we developed and evaluated a new free-breathing 3D stack-of-radial (free-breathing radial) technique for full volume placental R2* mapping at 3T. Free-breathing radial demonstrated good repeatability and established a nominal range of placental R2* in pregnant subjects during early gestation at 3T.