“…The ultrasound is representative for the noninvasive diagnostic techniques, and the most useful in the imaging of the fetus, fetal membrane, placenta, umbilical cord, blood flow, by the real-time 2D, 3D, 4D ultrasound, echocardiography, pulsed Doppler methods, color-and power Doppler flow mapping, from the sonoembryology, genetic fetal ultrasound, to the fetus passing through the pelvis in the delivery [8,9]. Fetal 2D, 3D and 4D ultrasound are presented in the topics of this special issue.…”