Is intrapartum vibratory acoustic stimulation a valid alternative to fetal scalp pH determination?
OBJECTIVES: To determine the association between fetal heart rate accelerations, whether spontaneous or induced by vibratory acoustic stimulation, and subsequent scalp pH values in presence of a suspicious intrapartum fetal heart rate tracing, and thereby assess the ability of accelerations to predict a concurrent normal fetal scalp blood pH. DESIGN: Prospective observational study of 253 labours involving 421 pH samples. SETTING: Tertiary care university hospital of Genoeva. INTERVENTION: Vibratory acoustic stimulation through the maternal abdominal wall for five seconds prior to fetal blood sampling. MAIN OUTCOME MEASURES: Spontaneous fetal heart rate reactivity (accelerations) in the 10 min preceding vibratory acoustic stimulation, vibratory acoustic-induced reactivity prior to fetal blood sampling, and scalp pH value. RESULTS: The positive predictive value of a reactive fetal heart rate response after vibratory acoustic stimulation was 78% (95% CI 73-84%) and 97% (95% CI 94-99%) fo
