Intrauterine effects of ultrasound: Animal studies

Abstract

During the past several decades, the use of ultrasound technology in the clinical setting has greatly increased. Because nearly every pregnant woman receives 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. Animal research has been important to the study of the effects of various exposures at all stages of pregnancy, since the clinical use of ultrasonography can 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 neurobehavioral effects. The preponderance of evidence from these studies indicates that, in the absence of a thermal effect, ultrasonography represents no measurable risk when used at recommended intensity levels. Teratology 59:240–251, 1999. © 1999 Wiley‐Liss, Inc.

Knowledge of the bio-effects of ultrasound among physicians performing clinical ultrasonography: Results of a survey conducted by the Italian Society for Ultrasound in Medicine and Biology (SIUMB)

“…The effects of US on organogenesis have also been studied in animals [6]. Significant adverse effects like abortion, malformation, or neuropsychic problems were reportedly absent when the intensity of US was maintained below the recommended values used in the clinical setting (since this precaution prevents temperature increases, which could be teratogenic), but, in some cases, small, yet statistically significant, reductions in birth weight were observed.…”

Biological effects of high-frequency ultrasound exposure during mouse organogenesis

“…The use of anesthesia or restraint during insonation could potentially confound the experimental results because both are associated with developmental toxicity (reviewed in Fisher et al 1994). Restraint stress is a well-known teratogen; however, there is no evidence that restraint of anesthetically induced unconscious mothers causes significant alterations in pregnancy outcome or postnatal behavior (Jensh and Brent 1999). The fact that similar results were found between litters born to anesthetized dams vs. dams not exposed to gestational anesthesia suggests no source of error from sedation.…”

Animal Models of Fetal Medicine and Obstetrics

“…The Doppler technology is based on analysis of the change in frequency or intensity of ultrasound waves when they are reflected by a moving target such as erythrocytes. Ultrasound exposure is considered harmless; and in fact, animal experiments subjected to fetal ultrasound imaging in various mammalian species showed no pathological effects for the embryo, no congenital malformations or adverse neurobehavioral effects [66]. The technique is often combined with simultaneous administration of a sonographic contrast agent, resulting in an enhanced gray scale or color Doppler signal, facilitating visualization of microvascular structures down to the microvascular perfusion.…”