Accuracy, Clinical Utility and Usability Study of a Wireless Self-Guided Fetal Heart Rate Monitor

Objective: To evaluate the accuracy, reliability, clinical utility, and usability of a wireless fetal and maternal heart rate monitor (HBM) when used by clinicians and pregnant women to monitor fetal heart rate (FHR). Methods: We recruited women aged 18 years or older with a singleton pregnancy of >12 weeks gestation. FHR recordings were performed using the HBM and cardiotocography (CTG) to determine comparative accuracy. The HBM was then used by clinicians and participants in the antenatal clinic with the latter then using the device unassisted to record at home. The women rated the HBM using the System Usability Scale (SUS). Results: A total of 81 participants provided 126 recordings for analysis. The accuracy of the HBM was excellent compared with CTG, with limits of agreement (95%) between minus 1.5 and plus 0.9 beats per minute (bpm) and a mean difference of minus 0.29 bpm. The FHR was detected on 100% of occasions by clinicians (52 recordings) and participants when used in the clinic (42 recordings) and at home (32 recordings). Home users took an average of 1.1 minutes to detect the FHR and recorded a continuous trace of >1 minute in 94% of occasions, with an average total trace time of 4.4 minutes. The FHR trace was deemed to be clinically useful in 100% of clinician recordings and 97% of home recordings. There was no effect from body mass index, gestational age, pregnancy history, or placental position. The HBM ranked in the 96th to 100th percentile on the SUS for usability and learnability. Conclusions: The HBM was accurate and easy for clinicians and participants to use. The data recorded at home was equivalent to that obtained in the clinic using current assessment protocols for low-risk pregnancies, allowing the device to be used in telehealth consultations. Clinical Trial Registration: Australian New Zealand Clinical Trial Registry, https://www.anzctr.org.au ACTRN12620000739910.