The safety of obstetric ultrasonography: concern for the fetus.

It has been estimated that more than half of all pregnant women in the United States undergo diagnostic ultrasound during their pregnancies. In light of this, the question of safety is of fundamental importance. Nondiagnostic ultrasound has been shown to produce biologic effects by thermal and cavitational activities. However, diagnostic ultrasound uses much lower intensities, and no evidence exists to suggest that it is associated with adverse effects. Numerous studies have examined the biologic effects of diagnostic ultrasound in insects, plants, cell suspensions, and even small mammals. The data from these experiments are confusing when attempting to relate these findings to the human. Epidemiologic data in humans, used to evaluate the potential adverse effects of exposure to diagnostic ultrasound, have revealed no ill effects from such exposure. Current data indicate that there are no confirmed biologic effects on patients and their fetuses from the use of diagnostic ultrasound and that the benefits to patients exposed to prudent use of diagnostic ultrasound outweigh the risks, if any. This review discusses the available information on the safety of obstetric ultrasonography.