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 s = 0.99, p