The use of vibroacoustic stimulation during the abnormal or equivocal biophysical profile

To determine whether vibroacoustic stimulation during the biophysical profile can change the fetal behavioral state and thus improve the score without increasing the false-negative rate of the test.

Eighty-one patients whose biophysical profile scores were 6 or lower after 15 minutes of observation had an electronic artificial larynx applied to the maternal abdomen in the region of the fetal head for 3 seconds, followed by continued observation for fetal movement, tone, and breathing for 15 minutes. We compared the obstetric and neonatal outcomes of 41 patients whose biophysical profile scores improved to normal after vibroacoustic stimulation with those of 283 patients whose scores were normal without vibroacoustic stimulation.

Vibroacoustic stimulation did improve an abnormal or equivocal biophysical profile score to normal in 67 of 81 cases (82%). No antepartum stillbirths or perinatal deaths occurred. There was no increase in the obstetric and neonatal complication rates of cesarean delivery for fetal distress, meconium staining of the amniotic fluid, and the incidence of small for gestational age infants.

Vibroacoustic stimulation improved the biophysical profile scores in most cases, an effect seen throughout the third trimester. Vibroacoustic stimulation did not appear to increase the false-negative rate of the biophysical profile and may reduce the incidence of unnecessary obstetric intervention.