While there are no known risks associated with diagnostic ultrasound, uncertainty about the safety of prenatal ultrasound exposure remains. The purpose of the present experiment was to evaluate the behavioral teratogenic potential of continuous‐wave (cw) ultrasound in rats, in the absence of maternal anesthesia or restraint. Pregnant CD rats, trained to remain immobile in a water‐filled ultrasound exposure tank, were scanned with 3 MHz cw ultrasound at levels of 0, 2, 10, 20, or 30 W/cm2|SPTA(spatial peak, temporal average intensity) on gestational days 4–20 for approximately 10 min/day. Offspring were examined postnatally for survival, growth, physical landmarks of development, behavioral development, and the adult functions of locomotor activity, learning and memory, and startle reactivity. No effects of prenatal ultrasound were found on maternal characteristics, offspring survival or growth, physical or behavioral landmarks of development, or adult tests of passive avoidance or startle. Effects at the highest intensity were obtained on corner and side locomotor activity and in a multiple‐T water maze on measures of errors of commission and time spent finding the goal. The results showed that prenatal cw ultrasound in rats can induce effects on some postnatal neurobehavioral functions at high exposure intensities (30 W/cm2), but at lower intensities (2–20 W/cm2) no consistent evidence of neurobehavioral effects was observed. © 1994 Wiley‐Liss, Inc.
ASJC Scopus subject areas
- Developmental Biology
- Health, Toxicology and Mutagenesis