A systematic scoping review to identify the design and assess the performance of devices for antenatal continuous fetal monitoring

Fig 1. PRISMA 2009 flow diagram of included studies. Adapted from Moher et al. [23].

Fig 2. Estimated average signal quality of fetal electrocardiography recordings from eight studies which used the Monica AN24 device. Black markers represent the signal quality with 95% confidence intervals (CI) (whiskers). The size of each grey square represents the relative weight in the meta-analysis. The diamond represents the signal quality summary value. Asterisk (*) represents studies which had the median and interquartile range/range data converted to the mean and standard deviation.

Fig 3. Success rates of unnamed fetal electrocardiography devices. Success rates presented as reported by the authors.

Fig 4. Device performance of fetal electrocardiography devices at different fetal gestational ages (weeks). The device performance (success rate or signal quality) for each study was extracted and reported in the figure using both the numerical value and a coloured key as a visual aid: green (≥80.0%), yellow (60.0–79.9%), orange (40.0–59.9%) and red (<40.0%). Four studies reported data only using a figure, hence data reported were extracted from the original figures either by drawing a line to the axis (Carter et al. and Graatsma et al. (2009)), or by dividing the number of successful recordings by the total number of recordings (Manella et al. and Taylor et al.). Kariniemi et al. did not provide a specific gestational age for “term”; for the purpose of this figure, term was assumed to be 40+0 weeks’ gestation. Numerical values reported are as presented in the studies, or to the nearest whole number if extrapolated from a figure. a Values represent success rate (as reported by authors). b Values represent signal quality. * Studies which used the Monica AN24 device.

Fig 5. Estimated average signal quality of fetal electrocardiograph recordings depending on time of day from three studies. Black markers represent the signal quality with 95% confidence intervals (CI) (whiskers). The size of each grey square represents the relative weight in the meta-analysis. The diamond represents the signal quality summary value. Asterisk (*) represents studies which had the median and interquartile range/range data converted to the mean and standard deviation. All studies included used the Monica AN24 device.

Fig 6. The number of studies included in the review published every two years. Devices have been split into the different technologies used: Fetal electrocardiography (fECG), fetal phonocardiography (fPCG), combined fECG/fPCG, accelerometry and fetal vectorcardiography (fVCG).