Three-dimensional Ultrasound (3DUS) has grown quickly and constantly over the last fifteen years. However, some of its best clinical uses remain to be defined. The threedimensional Power Doppler (PD) is based on the ability to register the signal amplitude of the ultrasound wave, which allows us to depict most moving particles in a given Region of Interest (ROI). It is also based on the three-dimensional US principles, that permit the collection of signals from such particles in a given Volume of Interest (VOI) The inclusion of a time sequencing protocol or a Space-Time Image correlation (STIC) algorithm, developed and made available to last generation US machines, adds the additional possibility of following the signal evolution during a pre-established lap. At first, this promising tool was used to evaluate vascularisation and perfusion in a series of foetal organs, finding neither adequate accuracy nor repeatability. Nowadays, its use in Foetal Medicine is restricted to certain foetal conditions, although new research is on-going and further uses for this technology are being unveiled.