A STUDY OF THE BIOEFFECTS OF MULTIPLE PRENATAL ULTRASOUND SCANS IN FETAL SHEEP

Objective: Multiple prenatal ultrasound scans in macaque monkeys have been shown to reduce newborn neutrophil and monocyte counts and to low er birth weight. The purpose of this study was to investigate if simil ar effects could also occur in a sheep model. Methods: Thirty pregnant Merino ewes were allocated at random to a protocol of multiple ultras ound scans involving a total of 440 min of insonation or to sham proce dures. Each fetus was delivered by caesarean section at 141 days gesta tion (term = 150 days). Results: There were no differences between the exposed and control groups in umbilical venous hematological paramete rs; mean birth weights; weights of the major organs; lengths of bones; markers of bone, liver, and thyroid metabolism; or bone mineral conte nt. Conclusions: The effects on hematological parameters and growth ob served after multiple prenatal ultrasound examinations in monkeys were not shown to occur in a fetal sheep model.