ABSTRACT: The Consensus Development Conference on Diagnostic Ultrasound Imaging revealed that neither the energy emitted from an ultrasound transducer, nor the energy absorbed by maternal and fetal tissues has been quantitated. For convenience, the energy is expressed in watts/square centimeter. Although in vitro and animal studies have shown various bioeffects of ultrasound, none obtained under 100 mW/cm2 has been reproducible, and none can be translated reliably to humans. Four randomized controlled trials of ultrasound imaging failed to show harmful effects, and also failed to show benefits of routine screening in terms of infant mortality or morbidity.
The panel accordingly recommended that ultrasound imaging be used only with a specific indication, and listed 27 indications. They recommended that women be supplied with information about exposure time, intensity, indication, alternatives, and benefits and risks of an ultrasound scan, if they request the information. The panel also recommended further research on outputs, bioeffects, and efficacy of routine screening by ultrasound during pregnancy.