Schiffer VMMM, Pellaers D, Hoenen JLJM, et al. - As placenta has a crucial role in establishing a healthy pregnancy, reliable non-invasive methods to estimate placental perfusion are desirable. Researchers here investigated the reproducibility and potential bias in different three-dimensional power Doppler (3DPD) methods appraising placenta perfusion. In this study, they included 10 singleton pregnancies around 16 weeks of gestation, with an anteriorly located placenta and centrally inserted umbilical cord. Placental perfusion was evaluated using eight different combinations of a specific placental sweep and sonobiopsy method. They used the 4D-view program for offline determination of vascularization index (VI), flow index (FI) and vascularization-flow index (VFI). Outcomes of three dimensional placental vascularization analysis indicated that whole placental sweep volume and centrally located, spherical sonobiopsy of 2 cm³ had the best reproducibility.