Intrauterine effects of ultrasound: human epidemiology

Ultrasound imaging has been used clinically as an effective diagnostic tool over the past 30 years. In spite of literally millions of examinations, there is no verified documented evidence of adverse effects in patients caused by exposure to diagnostic ultrasound. A number of epidemiological studies of intrauterine ultrasound exposure have been conducted, including several case-control and prospective randomized control studies. In some studies, an association of one or another bioeffect was identified, such as low birth weight, delayed speech, or increased incidence of left-handedness. However, with the exception of low birth weight, these findings have never been duplicated, and the great majority of such studies have been completely negative.