Vibroacoustic stimulation of the fetus entering the second stage of labor.

OBJECTIVE

To evaluate the fetal heart rate (FHR) response to vibroacoustic stimulation of fetuses entering the second stage of labor as a predictor of neonatal outcome.

METHODS

Three hundred sixteen cases and 316 controls were studied during the second stage of labor. All cases had vibroacoustic stimulation on entering the second stage of labor using an electronic artificial larynx. For control patients, the artificial larynx was not activated. The patients were stratified into groups based on the quality of FHR response: acceleration (n = 124), acceleration followed by deceleration (n = 120), and no response (n = 72).

RESULTS

Subsequent FHR accelerations and accelerations followed by decelerations were significantly more frequent in the study group than in controls (77.2 versus 15.2%; P < .05). The frequencies of low 5-minute Apgar scores (below 7) and low umbilical cord arterial pH (below 7.20) did not differ significantly in the group with the acceleration response when compared to those with acceleration followed by deceleration and the no-response groups. The incidence of nuchal cord was significantly higher for the group with a response pattern of acceleration followed by deceleration than for the acceleration and no-response groups (39.2 versus 10.5 versus 11.1%; P < .05).

CONCLUSIONS

Vibroacoustic stimulation in the second stage of labor is associated with FHR reactivity, but the quality of FHR response does not predict neonatal outcome and therefore appears to have little value in enhancing the management of the second stage of labor. However, an acceleration followed by deceleration response suggests the presence of nuchal cord.