Objective: To study the effect of sampling rate on the accuracy of fetal heart rate recording in labour.
Design: Prospective observational study.
Methods and subjects: The fetal heart rate was obtained from 153 fetuses in labour. The heart rate data was sampled at a rate of 0.5 Hz (every 2 s) and the means and standard deviations of 5-min segments compared against the mean and standard deviation for all beats in the same time interval.
Results: There was a highly significant correlation between the means (r = 0.994, p < 0.001) and standard deviations (r = 0.957, p < 0.001) of FHR sampled on successive beats compared with 2 s sampling.
Conclusion: Two second sampling of the fetal heart rate in labour will allow a highly complex analytical algorithm to process the signal in near real time for objective analysis.