Significance of oscillation frequency in intrapartum fetal monitoring

Until now, no statistical data have been available on the significance of the frequency of FHR oscillations. In order to evaluate the relation between oscillation frequency and neonatal outcome, the last 30 minutes of 812 FHR records were analyzed with respect to the number of 812 FHR records were analyzed with respect to the number of oscillations per minute only. Close correlations were found between slow oscillations below 2 per minute and the arterial cord pH as well as the Apgar scores after 1 and 5 minutes, respectively. No relation could be established between any oscillation frequency above 2 per minute and the measures of the neonatal outcome. In discussing the results, slow oscillations are suggested to be identical with the sinusoidal FHR. Emphasis is made that for an appropriate pattern recognition, true beat-to-beat recording is required, avoiding any averaging procedure.