Intrauterine effects of ultrasound: Animal studies

During the past several decades, the use of ultrasound technology in the cl inical setting has greatly increased. Because nearly every pregnant woman r eceives at least one sonographic procedure today, there has been developing concern about the safety of such procedures. Since ultrasound exposure can result in hyperthermia and other physiological effects, the determination of a threshold or no-effect exposure has become a high-priority goal. Anima l research has been important to the study of the effects of various exposu res at all stages of pregnancy, since the clinical use of ultrasonography c an occur during the preimplantation, organogenic, and fetal stages. Animal experiments using various mammalian species have been able to determine no- effect exposure levels for embryonic loss, congenital malformations and neu robehavioral effects. The preponderance of evidence from these studies indi cates that, in the absence of a thermal effect, ultrasonography represents no measurable risk when used at recommended intensity levels. (C) 1999 Wile y-Liss, Inc.