[What do doctors understand regarding ultrasound safety during pregnancy?].

Ultrasound has a well established record for being a safe procedure during pregnancy. Nevertheless, one should bear in mind the fact that ultrasound is a source of energy with two main bioeffects in tissue: heat and cavitation. These effects are inherent in the physical properties of the ultrasound transducers and have not been shown to be harmful to the developing fetus. The two bioeffects are approximated by the thermal index for heating (TI) and the mechanical index (MI) for cavitation effects. These indices appear clearly on the ultrasound screen, enabling the operator to see if their values are within the normal range. Poor level of knowledge regarding safety issues were found among ultrasound performers both in Israel and the USA. This lack of knowledge is an alarm signal for the health authorities, arousing a demand for the establishment of training programs for all ultrasound end-users.