Reproducibility of automated fetal heart rate measurement using a novel technique with two-dimensional tracking.

Purpose: To assess the accuracy of automated fetal heart rate measurement using two-dimensional tracking (AutoFHR) by comparison with the conventional free-angle M-mode (M-mode) and pulsed-waved Doppler (PWD) methods.

Methods: A multicenter prospective comparative study was conducted. AutoFHR is a novel technique for the automatic calculation of fetal heart rate using a two-dimensional speckle-tracking method. The fetal heart rate (FHR) obtained by AutoFHR was compared with that obtained by the conventional M-mode and PWD. Statistical analysis was performed on the correlation between the FHR measured by AutoFHR and that determined by M-mode and PWD.

Results: Data from 326 singleton pregnancies were analyzed, and all the data and the data from 178 cases were compared with M-mode and PWD, respectively. The intraobserver ICC was 0.96 (95% CI: 0.93-0.98), whereas the interobserver ICC was 0.97 (95% CI: 0.95-0.99). Systematic bias was not observed between M-mode and PWD, based on the Bland-Altman plots. Analyses of the relationships among the FHRs yielded by each method revealed that AutoFHR was strongly associated with M-mode (r = 0.99, p < 0.001) and PWD (r = 0.86, p < 0.001).

Conclusion: Evaluation of FHR by AutoFHR was proved to be equivalent to evaluation by the conventional M-mode and PWD. AutoFHR can be employed with only B-mode data, making FHR measurement easier and safer.