Intrapartum vibratory acoustic stimulation after maternal meperidine administration.

OBJECTIVE: To examine the effectiveness of the acoustic stimulation test in the interpretation of suspicious cardiotocograms obtained after meperidine administration to the mother during the first stage of labor. SUBJECTS AND METHODS: We studied 45 unselected parturients who received 50 mg meperidine i.m. when cervical dilatation was 5 cm. In all cases a decreased beat-to-beat variability of the fetal heart rate and fetal movements was noted after the injection of meperidine. A vibratory acoustic stimulation was performed in 25 patients (group A) while the remaining 20 (group B) had no stimulation. RESULTS: After the meperidine injection, the acoustic-induced reactivity returned immediately in group A, while the spontaneous reactivity returned 30 minutes later. The mean number of fetal movements in all parturients was 8.71 +/- 2.18 before meperidine administration. Sixty minutes after the meperidine injection the mean number was 8.52 +/- 2.48 in group A and 1.65 +/- 1.81 in group B (p < 0.0001). CONCLUSION: The acoustic stimulation test is an effective method of interpreting suspicions CTG's obtained after meperidine administration to the mother during the first stage of labour.