VIBROACOUSTIC STIMULATION OF THE FETUS ENTERING THE 2ND STAGE OF LABOR

Objective: To evaluate the fetal heart rate (FHR) response to vibroaco ustic stimulation of fetuses entering the second stage of labor as a p redictor 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 u sing an electronic artificial larynx. For control patients, the artifi cial larynx was not activated. The patients were stratified into group s based on the quality of FHR response: acceleration (n = 124), accele ration followed by deceleration (n = 120), and no response (n = 72). R esults: Subsequent FHR accelerations and accelerations followed by dec elerations were significantly more frequent in the study group than in controls (77.2 versus 15.2%; P < .05). The frequencies of low 5-minut e Apgar scores (below 7) and low umbilical cord arterial pH (below 7.2 0) did not differ significantly in the group with the acceleration res ponse when compared to those with acceleration followed by deceleratio n and the no-response groups. The incidence of nuchal cord was signifi cantly higher for the group with a response pattern of acceleration fo llowed by deceleration than for the acceleration and no-response group s (39.2 versus 10.5 versus 11.1%; P < .05). Conclusions: Vibroacoustic stimulation in the second stage of labor is associated with FHR react ivity, but the quality of FHR response does not predict neonatal outco me and therefore appears to have little value in enhancing the managem ent of the second stage of labor. However, an acceleration followed by deceleration response suggests the presence of nuchal cord.