Vibroacoustic stimulation for risk assessment.

VAS of the human fetus produces a profound alteration of fetal behavior and FHR. Many authors have reported on the success of the technique in improving the efficiency of antepartum FHR testing without altering the predictive reliability of the tests. VAS has other potential advantages in the antepartum assessment of fetal well-being and provocation of fetal activity to improve ultrasonographic anatomic visualization. Experimentally, VAS offers a unique opportunity to assess how the fetus responds to its external environment. The information currently available suggests that exposure of the fetus to VAS is safe in its present clinical applications. Additional investigation is needed to characterize the best frequency, duration, intensity, and choice of stimulus to provide the most consistent responses. The literature to date presents a confusing array of studies that have used different methodologies, making comparisons of studies difficult. It is the opinion of the author that VAS is a safe clinical technique as currently employed.