Fetal heart rate development during labour

Figures

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  Fig. 1. Signals acquired from the Moyo fetal heart rate monitor is used as the input for our analysis framework in this work. Noise is first removed on the FHR signals, before group analysis is conducted. The acceleration signal present in the Moyo has previously been shown to identify contractions [15], but it is not used in the work presented in this paper

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  Fig. 2. Example of the result using FhrClean. The original FHR signal with noise on top, and the corresponding signal with noise removed, bottom

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  Fig. 3. Overview of the probability density for all measured heart rates in a, the probability density for the removed heart rates in b, and the percentage of heart rate measurements identified as noise and removed the last 150 min before birth in c

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  Fig. 4. a Distribution of the MHR and FHR from all time points in the dataset where both values are measured. b The absolute difference between the corresponding pairs of MHR and FHR. The found MHR/FHR ambiguity of 4.53% is illustrated with the red bar

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  Fig. 5. Trend of the FHR the last 150 min before birth. Solid lines indicate the median heart rate, and the matching dashed lines the 25 and 75 percentiles. Computed using non-overlapping 10-min intervals

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  Fig. 6. Trend of the FHR the last 150 min before birth. Solid lines indicate the median heart rate, and the matching dashed lines the 25 and 75 percentiles. Computed using non-overlapping 5-min intervals

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  Fig. 7. Trend of the FHR the last 150 min before birth. Solid lines indicate the median heart rate, and the matching dashed lines the 25 and 75 percentiles. Computed using non-overlapping 10-min intervals

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  Fig. 8. Estimated pdf of the measured heart rate the last 90 min before birth, divided in 30-min windows. a Estimated pdf for the last 90–60 min before birth. b Estimated pdf for the last 60–30 min before birth. c Estimated pdf for the last 30 min before birth

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  Fig. 9. Estimated pdf changes over time, neonates defined as normal 24 h after birth

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  Fig. 10. Estimated pdf changes over time, neonates admitted to NCU 24 h after birth

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  Fig. 11. Moyo fetal heart rate monitor, Laerdal Global Health AS, Norway. Illustration reproduced with permission [17]

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  Fig. 12. Example signals from the Moyo fetal heart rate monitor. The top plot includes the FHR, shown in blue, and MHR, shown in red. The red dashed lines indicate the normal FHR region during labour. An example of the noise removed by FhrClean is illustrated in the green circle. The second plot shows the three axes measured from the accelerometer. The MHR is intermittent measured at −343 min. A zoomed version of the maternal ECG, with visible R-waves is shown on the bottom