Review Article
Kazuo Maeda*
Abstract
Although no adverse effect of ultrasound diagnosis has been reported, the safety of diagnostic ultrasound has been discussed since its introduction into clinical study in 1950s, because real-time 2D, 3D, 4D ultrasound imaging, pulsed Doppler flow wave, color Doppler, fetal monitor, fetal movement, are indispensable in obstetric and gynecologic studies, particularly in the studies on the fetus.