Relative accuracy of computerized intrapartum fetal heart rate pattern recognition by ultrasound and abdominal electrocardiogram detection

Power-MF: robust fetal QRS detection from non-invasive fetal electrocardiogram recordings

Objective.Perinatal asphyxia poses a significant risk to neonatal health, necessitating accurate fetal heart rate monitoring for effective detection and management. The current gold standard, cardiotocography, has inherent limitations, highlighting the need for alternative approaches. The emerging technology of non-invasive fetal electrocardiography shows promise as a new sensing technology for fetal cardiac activity, offering potential advancements in the detection and management of perinatal asphyxia. Although algorithms for fetal QRS detection have been developed in the past, only a few of them demonstrate accurate performance in the presence of noise and artifacts.Approach.In this work, we proposePower-MF, a new algorithm for fetal QRS detection combining power spectral density and matched filter techniques. We benchmarkPower-MFagainst three open-source algorithms on two recently published datasets (Abdominal and Direct Fetal ECG Database: ADFECG, subsets B1 Pregnancy and B2 Labour; Non-invasive Multimodal Foetal ECG-Doppler Dataset for Antenatal Cardiology Research: NInFEA).Main results.Our results show thatPower-MFoutperforms state-of-the-art algorithms on ADFECG (B1 Pregnancy: 99.5% ± 0.5% F1-score, B2 Labour: 98.0% ± 3.0% F1-score) and on NInFEA in three of six electrode configurations by being more robust against noise.Significance.Through this work, we contribute to improving the accuracy and reliability of fetal cardiac monitoring, an essential step toward early detection of perinatal asphyxia with the long-term goal of reducing costs and making prenatal care more accessible.

Performance of a Maternal Abdominal Surface Electrode System for Fetal Heart Rate and Uterine Contraction Monitoring from 34 to 37 Weeks

OBJECTIVE

 The objective of this study was to compare performance of a maternal surface electrode patch with ultrasound- and tocodynamometer-based monitoring to detect fetal heart rate and uterine contractility in late preterm labors.

STUDY DESIGN

 Thirty women between 340/7 and 366/7 weeks' gestation were monitored simultaneously with a Doppler/tocodynamometer system and a wireless fetal-maternal abdominal surface electrode system. Fetal and maternal heart rate and uterine contraction data from both systems were compared. Reliability was measured by the success rate and percent agreement. Deming regression and Bland-Altman analysis estimated the concordance between the systems. Uterine contractions were assessed by visual interpretation of monitor tracings.

RESULTS

 The success rate for the surface electrode system was 89.5% (95% confidence interval [CI], 85.7-93.3), and for ultrasound it was 88.4% (95% CI, 84.9-91.9; p = 0.73), with a percent agreement of 88.1% (95% CI, 84.2-92.8). Results were uninfluenced by the patients' body mass. The mean Deming slope was 1 and the y-intercept was -3.0 beats per minute (bpm). Bland-Altman plots also showed a close relationship between the methods, with limits of agreement less than 10 bpm. The percent agreement for maternal heart rate was 98.2% (95% CI, 97.4-98.8), and for uterine contraction detection it was 89.5% (95% CI, 85.5-93.4).

CONCLUSION

 Fetal heart rate and uterine contraction monitoring at 340/7 to 366/7 weeks using abdominal surface electrodes was not inferior to Doppler ultrasound/tocodynamometry for fetal-maternal assessment.

REGISTRATION

 clinicaltrials.gov/February 20, 2017/identifier NCT03057275.

KEY POINTS

· Monitoring the preterm fetal heart rate with surface electrodes is feasible.. · Preterm contractions can be monitored with surface electrodes.. · The technique was noninferior to standard external monitors..

Australian women's experiences of wearing a non-invasive fetal electrocardiography (NIFECG) device during labour

BACKGROUND

Continuous electronic fetal monitoring devices can restrict women's freedom of movement and choice of positioning during labour and birth. Despite the use of continuous electronic fetal monitoring for the past 50 years, little attention has been paid to women's experiences of wearing different fetal monitoring devices in labour.

AIM

To explore women's views and experiences of wearing a beltless continuous electronic fetal monitoring device, the non-invasive fetal electrocardiogram during labour.

METHODS

A qualitative descriptive approach was taken. Recruitment was via a larger clinical feasibility study. Some women who consented to take part in the clinical feasibility study also consented to being interviewed during the postnatal period. Transcripts were thematically analysed.

FINDINGS

Women reported improved comfort when wearing the non-invasive fetal electrocardiogram device. They appreciated how it enabled freedom of movement and an ability to actively participate in labour. They compared their experience with previous use of cardiotocography which they felt compromised their bodily autonomy. All forms of continuous electronic fetal monitoring experienced by women resulted in the unwelcome experience of 'Poking and prodding' by the midwife.

DISCUSSION

Continuous electronic fetal monitoring can negatively impact women's labour and birth experience, particularly when the measurement of fetal wellbeing is prioritised.

CONCLUSION

The way in which continuous electronic fetal monitoring technology is designed and used is an important component of optimising physiological processes and positive experiences for women during labour and birth for women with complex pregnancies. Non-invasive fetal electrocardiograpy is a promising additional option for women.

Saleh A, Md Tahir N, Najim HT, Taher M. Intrapartum cardiotocography trace pattern pre-processing, features extraction and fetal health condition diagnoses based on RCOG guideline

CONTEXT

The computerization of both fetal heart rate (FHR) and intelligent classification modeling of the cardiotocograph (CTG) is one of the approaches that are utilized in assisting obstetricians in conducting initial interpretation based on (CTG) analysis. CTG tracing interpretation is crucial for the monitoring of the fetal status during weeks into the pregnancy and childbirth. Most contemporary studies rely on computer-assisted fetal heart rate (FHR) feature extraction and CTG categorization to determine the best precise diagnosis for tracking fetal health during pregnancy. Furthermore, through the utilization of a computer-assisted fetal monitoring system, the FHR patterns can be precisely detected and categorized.

OBJECTIVE

The goal of this project is to create a reliable feature extraction algorithm for the FHR as well as a systematic and viable classifier for the CTG through the utilization of the MATLAB platform, all the while adhering to the recognized Royal College of Obstetricians and Gynecologists (RCOG) recommendations.

METHOD

The compiled CTG data from spiky artifacts were cleaned by a specifically created application and compensated for missing data using the guidelines provided by RCOG and the MATLAB toolbox after the implemented data has been processed and the FHR fundamental features have been extracted, for example, the baseline, acceleration, deceleration, and baseline variability. This is followed by the classification phase based on the MATLAB environment. Next, using the guideline provided by the RCOG, the signals patterns of CTG were classified into three categories specifically as normal, abnormal (suspicious), or pathological. Furthermore, to ensure the effectiveness of the created computerized procedure and confirm the robustness of the method, the visual interpretation performed by five obstetricians is compared with the results utilizing the computerized version for the 150 CTG signals.

RESULTS

The attained CTG signal categorization results revealed that there is variability, particularly a trivial dissimilarity of approximately (+/-4 and 6) beats per minute (b.p.m.). It was demonstrated that obstetricians' observations coincide with algorithms based on deceleration type and number, except for acceleration values that differ by up to (+/-4).

DISCUSSION

The results obtained based on CTG interpretation showed that the utilization of the computerized approach employed in infirmaries and home care services for pregnant women is indeed suitable.

CONCLUSIONS

The classification based on CTG that was used for the interpretation of the FHR attribute as discussed in this study is based on the RCOG guidelines. The system is evaluated and validated by experts based on their expert opinions and was compared with the CTG feature extraction and classification algorithms developed using MATLAB.

Heart rate markers for prediction of fetal acidosis in an experimental study on fetal sheep

To overcome the difficulties in interpreting fetal heart rate (FHR), several tools based on the autonomic nervous system and heart rate variability (HRV) have been developed. The objective of this study was to use FHR and HRV parameters for the prediction of fetal hypoxia. It was an experimental study in the instrumented fetal sheep. Repeated umbilical cord occlusions were performed to achieve severe acidosis. Hemodynamic parameters, ECG, and blood gases were analyzed. The variables used were heart rate baseline, HRV analysis (RMSSD, SDNN, LF, HF, HFnu, Fetal Stress Index (FSI), …), and morphological analysis of decelerations. The gold standard used to classify hypoxia was the fetal arterial pH (pH < 7.10). Different multivariable statistical methods (logistic regression and decision trees) were applied for the detection of acidosis. 21 lambs were instrumented. A total of 130 pairs of FHR/fetal pH analysis were obtained of which 29 in the acidosis group and 101 in the non-acidosis group. After logistic regression model with bootstrap resampling and stepwise backward selection, only one variable was selected, FSI. The AUC of FSI alone in this model was 0.81 with a sensitivity of 0.66, specificity of 0.88, PPV of 0.61, and NPV of 0.90 considering a threshold of 68. Decision trees with CHAID and CART algorithms showed a sensitivity of 0.48 and 0.59, respectively, and a specificity of 0.94 for both. All employed methods identified HRV variables as the most predictive of acidosis. The primary variables selected automatically were those from the HRV. Supporting the use of FHRV measures for the screening of fetal acidosis during labour is interesting.

Ultrasound Doppler fetal heart rate detection algorithm analyzes the correlation between twin selective fetal growth restriction and cord blood SFass fasL level

Objective

The paper uses ultrasound Doppler fetal heart rate detection algorithm to explore the placental characteristics of monochorionic twin pregnancy with selective fetal growth restriction, and discuss the correlation between selective fetal growth restriction and cord blood SFass FasL level.

Methods

From June 1, 2019 to June 1, 2020 in our hospital, 23 cases of selective fetal growth restriction and 32 cases of uncomplicated cases were included in the monochorionic twin pregnancies whose pregnancy was terminated in our hospital (control group) research. Perfusion was completed within 24 hours after delivery of the placenta. The umbilical arteries and veins of the two fetuses were respectively perfused with four different colors of pigments. The type of anastomoses was judged according to the color of the blood vessels on the placenta surface.

Results

The selective fetal growth restriction group was higher than the control group. In the selective fetal growth restriction group and the control group, the number of anastomoses of the placental superficial arterial artery, arterial vein and venous vein were 1.0 and 1.0, 3.0 and 2.0, 0.0 and 0.0, respectively; the placental superficial arterial artery, arterial vein and venous vein. The total diameters of the anastomosed blood vessels were 2.7 and 2.2, 4.0 and 3.4, 0.0 and 0.0 mm, respectively; the total number of superficial placental anastomosed blood vessels in the selective fetal growth restriction group and the control group were 3.5 and 3.5, respectively.The total diameters were 6.9 and 6.9, respectively 5.9mm.

Conclusion

Uneven placental share and non-central attachment of the umbilical cord may be risk factors for selective fetal growth restriction in monochorionic twin pregnancy.

Is short-term-variation of fetal-heart-rate a better predictor of fetal acidaemia in labour? A feasibility study

Background

Continuous intrapartum fetal monitoring is challenging and its clinical benefits are debated. The project evaluated whether short-term-variation (STV) and other computerised fetal heart rate (FHR) parameters (baseline FHR, long-term-variation, accelerations and decelerations) predicted acidaemia at birth. The aims of the study were to assess the changes in FHR pattern during labour and determine the feasibility of undertaking a definitive trial by reporting the practicalities of using the monitoring device, participant recruitment, data collection and staff training.

Methods

200 high-risk women carrying a term singleton, non-anomalous fetus, requiring continuous FHR monitoring in labour were consented to participate from the Jessop Wing maternity unit, Sheffield, UK. The trans-abdominal fetal ECG monitor was placed as per clinical protocol. During the monitoring session, clinicians were blinded to the computerised FHR parameters. We analysed the last hour of the FHR and its ability to predict umbilical arterial blood pH <7.20 using receiver operator characteristics (ROC) curves.

Results

Of 200 women, 137 cases were excluded as either the monitor did not work from the onset of labour (n = 30), clinical staff did not return or used the monitor on another patient (n = 37), umbilical cord blood not obtained (n = 25), FHR data not recorded within an hour of birth (n = 34) and other reasons (n = 11). In 63 cases included in the final analysis, the computer-derived FHR parameters did not show significant correlation with umbilical artery cord pH <7.20. Labour was associated with a significant increase in short and long term variation of FHR and number of deceleration (P<0.001). However, baseline FHR decreased significantly before delivery (P<0.001).

Conclusions

The project encountered a number of challenges, with learning points crucial to informing the design of a large study to evaluate the potential place of intrapartum computerised FHR parameters, using abdominal fetal ECG monitor before its clinical utility and more widespread adoption can be ascertained.