Spatiotemporal electrohysterography patterns in normal and arrested labor

doi:10.1016/j.ajog.2008.09.008

American Journal of Obstetrics and Gynecology

Volume 200, Issue 1, January 2009, Pages 54.e1-54.e7

https://doi.org/10.1016/j.ajog.2008.09.008 Get rights and content

Objective

The purpose of this study was to investigate the spatiotemporal patterns of uterine electrical activity in normal and arrested labors.

Study Design

From a database of electrohysterograms, 12 subjects who underwent cesarean delivery for active-phase arrest were each matched with 2 vaginally delivered controls. Using 30-minute segments of the electrohysterogram during the arrest, or the same dilation in controls, the center of uterine electrical activity was derived. The vertical motion of this center of uterine activity was determined for each contraction and the frequencies of movement patterns analyzed.

Results

Predominantly upward movement of the center of uterine activity (longer and/or stronger contraction at the fundus) was more common with normal dilation (P = .003). Receiver operating characteristic curve analysis gave an area under the curve of 0.91 for predicting outcome (vaginal vs cesarean delivery).

Conclusion

There is a significant correlation between upward movement of the center of uterine activity (fundal dominance) and current labor progress.

Section snippets

Materials and Methods

We conducted a case-control study using data derived from a larger study designed to noninvasively collect fetal electrocardiographic (ECG) and uterine electrical activity, represented by the electrohysterogram, or EHG. Following University of Florida College of Medicine Institutional Review Board approval, the protocol was instituted in 2001 at Shands Hospital at the University of Florida. The service consists of resident physicians supervised by faculty and fellows. All patients admitted for

Results

The average duration of arrest in the cesarean delivery cohort was 6 ± 3 hours. All arrest patients and 17/24 vaginally delivered patients received oxytocin augmentation. All patients had a sustained contraction frequency of every 1-3 minutes, and of the 11 cesarean patients who had intrauterine pressure (IUP) monitoring, all achieved Montevideo units (MVU) > 150 mmHg. The groups were not significantly different with regard to the pairing variables (gestational age, BMI, dilation at

Comment

Intrapartum assessment of uterine activity is routinely employed to guide active management of labor and delivery. The goal of such management is 2-fold: (1) progress in labor resulting in vaginal delivery, and (2) identification of unsuccessful labor that requires cesarean delivery. While the gold standard for assessing labor progress is serial cervical examinations, the risk of infection coupled with the inherent inaccuracy of the measure limits its use for assessment at intervals of less

Acknowledgments

The authors are grateful to Keith Muller, PhD, J. R. Clemmons, and Q. Li for statistical analyses. Dr Muller is Professor and Director of the Division of Biostatistics, Department of Epidemiology and Health Policy Research, University of Florida College of Medicine. Mr Clemmons and Ms Li are Coordinators, Statistical Research, Institute for Child Health Policy, University of Florida. The authors are also grateful to Laura Tripp, RN, and Erin Tighe for their data collection and research

References (26)

D.S. Gifford et al.
Lack of progress in labor as a reason for cesarean
Obstet Gynecol
(2000)
D.J. Rouse et al.
Active phase labor arrest: revisiting the 2-hour minimum
Obstet Gynecol
(2001)
L.Y. Hin et al.
Antepartum and intrapartum prediction of cesarean need: risk scoring in singleton pregnancies
Obstet Gynecol
(1997)
M. Letic
Inaccuracy in cervical dilatation assessment and the progress of labour monitoring
Med Hypotheses
(2003)
J.Y. Phelps et al.
Accuracy and intraobserver variability of simulated cervical dilatation measurements
Am J Obstet Gynecol
(1995)
Y. Sharf et al.
Continuous monitoring of cervical dilatation and fetal head station during labor
Med Eng Physics
(2007)
H. Eswaran et al.
First magnetomyographic recordings of uterine activity with spatial-temporal information with a 151-channel sensor array
Am J Obstet Gynecol
(2002)
L. Spatling et al.
External 4-channel tocography during delivery
Int J Gynecol Obstet
(1994)
J.E. Althaus et al.
Cephalopelvic disproportion is associated with an altered uterine contraction shape in the active phase of labor
Am J Obstet Gynecol
(2006)
R.E. Garfield et al.
Comparing uterine electromyography activity of antepartum patients versus term labor patients
Am J Obstet Gynecol
(2005)

W.L. Maner et al.

Predicting term and preterm delivery with transabdominal uterine electromyography

Obstet Gynecol

(2003)

I. Verdenik et al.

Uterine electrical activity as predictor of preterm birth in women with preterm contractions

Eur J Obstet Gynecol Reprod Biol

(2001)

J.A. Martin et al.

Births: final data for 2004National vital statistics reports 55(1)

(2006)

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Multi-channel electrohysterography enabled uterine contraction characterization and its effect in delivery assessment
2023, Computers in Biology and Medicine
Uterine contractions are routinely monitored by tocodynamometer (TOCO) at late stage of pregnancy to predict the onset of labor. However, TOCO reveals no information on the synchrony and coherence of contractions, which are important contributors to a successful delivery. The electrohysterography (EHG) is a recording of the electrical activities that trigger the local muscles to contract. The spatial–temporal information embedded in multiple channel EHG signals make them ideal for characterizing the synchrony and coherence of uterine contraction. To proceed, contractile time-windows are identified from TOCO signals and are then used to segment out the simultaneously recorded EHG signals of different channels. We construct sample entropy SamEn and Concordance Correlation based feature $ψ$ from these EHG segments to quantify the synchrony and coherence of contraction. To test the effectiveness of the proposed method, 122 EHG recordings in the Icelandic EHG database were divided into two groups according to the time difference between the gestational ages at recording and at delivery (TTD). Both SamEn and $ψ$ show clear difference in the two groups ( $p < 1 0^{- 5}$ ) even when measurements were made 120 h before delivery. Receiver operating characteristic curve analysis of these two features gave AUC values of 0.834 and 0.726 for discriminating imminent labor defined with TTD $\leq$ 24 h. The SamEn was significantly smaller in women (0.1433) of imminent labor group than in women (0.3774) of the pregnancy group. Using an optimal cutoff value of SamEn to identify imminent labor gives sensitivity, specificity, and accuracy as high as 0.909, 0.712 and 0.743, respectively. These results demonstrate superiority in comparing to the existing SOTA methods. This study is the first research work focusing on characterizing the synchrony property of contractions from the electrohysterography signals. Despite the very limited dataset used in the validation process, the promising results open a new direction to the use of electrohysterography in obstetrics.
Monitoring uterine contractions during labor: current challenges and future directions
2023, American Journal of Obstetrics and Gynecology
Organ-level models are used to describe how cellular and tissue-level contractions coalesce into clinically observable uterine contractions. More importantly, these models provide a framework for evaluating the many different contraction patterns observed in laboring patients, ideally offering insight into the pitfalls of currently available recording modalities and suggesting new directions for improving recording and interpretation of uterine contractions. Early models proposed wave-like propagation of bioelectrical activity as the sole mechanism for recruiting the myometrium to participate in the contraction and increase contraction strength. However, as these models were tested, the results consistently revealed that sequentially propagating waves do not travel long distances and do not encompass the gravid uterus. To resolve this discrepancy, a model using 2 mechanisms, or a “dual model,” for organ-level signaling has been proposed. In the dual model, the myometrium is recruited by action potentials that propagate wave-like as far as 10 cm. At longer distances, the myometrium is recruited by a mechanotransduction mechanism that is triggered by rising intrauterine pressure. In this review, we present the influential models of uterine function, highlighting their main features and inconsistencies, and detail the role of intrauterine pressure in signaling and cervical dilation. Clinical correlations demonstrate the application of organ-level models. The potential to improve the recording and clinical interpretation of uterine contractions when evaluating labor is discussed, with emphasis on uterine electromyography. Finally, 7 questions are posed to help guide future investigations on organ-level signaling mechanisms.
Quantitative analysis for grading uterine electromyography activities during labor
2023, American Journal of Obstetrics and Gynecology MFM
Citation Excerpt :
EMG activity was also reflective of the frequency and intensity of uterine contraction. Recent advances in EMG have therefore been applied in both clinical practice and research, including the prediction of preterm birth,5,6 parturition,7,8 and labor arrest9,10 and the evaluation of the effects of tocolysis,11–14 oxytocin,10 and patient-controlled epidural analgesia (PCEA)15–17on EMG activities and outcomes in labor. EMG is recognized as an effective means of pregnancy and delivery monitoring, but it is still not widely used in the clinical setting.
The strength of uterine contraction is one of the decisive factors for labor progression and parturition. Clinicians usually encounter difficulties in early identification of inadequate contractions and in oxytocin treatment. Electromyography—an emerging technology for uterine contraction monitoring—can quantify the intensity of myoelectric activity of uterine contraction. Therefore, grading patients with different uterine contraction intensities by electromyography is of great significance to the clinical intensive management of uterine contraction and labor process.
This study aimed to quantify and grade electromyography activity during the latent phase of the first stage of labor and explore its relationship with oxytocin treatment and length of labor.
We performed a retrospective cohort study to identify electromyography parameters as a predictor for oxytocin treatment and length of labor among a cohort of term singleton primipara (n=508) during the latent phase who delivered in Guangzhou between August 2018 and December 2021. The electromyography parameters were graded according to the quartile method, and the significance of grading and delivery outcome was explored. Univariate and multivariate logistic regression were used to determine the predictors of oxytocin treatment.
Maternal gestational age (adjusted risk ratio, 1.2; 95% confidence interval, 1.0–1.5), root mean square (adjusted risk ratio, 0.01; 95% confidence interval, 0.004–0.03), and power (adjusted risk ratio, 0.02; 95% confidence interval, 0.01–0.05) were significant predictors of oxytocin argumentation. The low electromyography activity group had a longer first stage labor and total labor time and were more likely to use oxytocin.
Electromyography parameters root mean square and power had high predictive values for later oxytocin treatment among patients with spontaneous labor. Patients with low-grade electromyography were more likely need oxytocin treatment. Electromyography grading is very important for its clinical promotion and use, and it could lead to more reliable analyses of oxytocin treatments and eventually to more effective interventions to prevent prolonged labor.
Regional identification of information flow termination of electrohysterographic signals: Towards understanding human uterine electrical propagation
2022, Computer Methods and Programs in Biomedicine
Background and Objective: The uterine electrohysterogram (EHG) contains important information about electrical signal propagation which may be useful to monitor and predict the progress of pregnancy towards parturition. Directed information processing has the potential to be of use in studying EHG recordings. However, so far, there is no directed information-based estimation scheme that has been applied to investigating the propagation of human EHG recordings. To realize this, the approach of directed information and its reliability and adaptability should be scientifically studied.
Methods: We demonstrated an estimation scheme of directed information to identify the spatiotemporal relationship between the recording channels of EHG signal and assess the algorithm reliability initially using simulated data. Further, a regional identification of information flow termination (RIIFT) approach was developed and applied for the first time to extant multichannel EHG signals to reveal the terminal zone of propagation of the electrical activity associated with uterine contraction. RIIFT operates by estimating the pairwise directed information between neighboring EHG channels and identifying the location where there is the strongest inward flow of information. The method was then applied to publicly-available experimental data obtained from pregnant women with the use of electrodes arranged in a $4 - b y - 4$ grid.
Results: Our results are consistent with the suggestions from the previous studies with the added identification of preferential sites of excitation termination - within the estimated area, the direction of surface action potential propagation towards the medial axis of uterus during contraction was discovered for $72.15 %$ of the total cases, demonstrating that our RIIFT method is a potential tool to investigate EHG propagation for advancing our understanding human uterine excitability.
Conclusions: We developed a new approach and applied it to multichannel human EHG recordings to investigate the electrical signal propagation involved in uterine contraction. This provides an important platform for future studies to fill knowledge gaps in the spatiotemporal patterns of electrical excitation of the human uterus.
A study of uterine inertia on the spontaneous of labor using uterine electromyography
2021, Taiwanese Journal of Obstetrics and Gynecology
Citation Excerpt :
Thus, the physiological control of uterine contractile events is important in understanding this condition. Uterine contractility is recognized as being regulated by excitability of the muscle of the uterus (myometrium) and movement of charged ions between the interior and exterior muscle cells to produce voltage changes (bursts) that propagate throughout the uterus to produce synchronization of contractility. [16–18] Contractions of the myometrium are directly related to electrical bursts within the muscle cells [16].
The purpose of this study is to analyze uterine electromyography burst patterns in patients with spontaneous labor and patients with uterine inertia.
Uterine electromyography was recorded using 4 silver/silver chloride electrodes placed periumbilical. Thirty women in the spontaneous labor were enrolled. Uterine electromyography was also recorded from patients with uterine inertia before and after oxytocin treatment. EMG bursts were characterized by analysis of multiple variables including burst frequency, duration, root mean squared, amplitude, and total power.
There were significant reductions (P < .01) in all EMG burst characteristics. In addition, uterine electromyography parameters were all increased after oxytocin treatment and were comparable (P > .05) to patients in spontaneous labor.
Uterine electromyography can be used effectively to distinguish patients progressing with spontaneous labor from patients that develop uterine inertia. Uterine inertia is characterized by reduced EMG activity and failure of cervical dilation. Uterine electromyography is a quantitative, non-invasive assessment tool that contributes to the diagnosis, evaluation and management of patients with spontaneous labor and uterine inertia.
Performance comparison of coupling-evaluation methods in discriminating between pregnancy and labor EHG signals
2021, Computers in Biology and Medicine
Citation Excerpt :
Our results generally coincide with other study results (except one) regarding the increasing connectivity trend from pregnancy to labor. Regarding the direction of propagation, our results coincide with [16,17] that show multi-directionality with a concentration towards the cervix (bottom), partially coincide with [11,20] that indicates both upward and downward propagation direction, and also with [15] that found no preferred propagation direction. One of the limitations of our study is that the proposed filtering-windowing framework is not suitable for real-time applications as the entire contraction signal must be present prior to starting stationary segmentation preprocessing.
Recent years have seen an increased interest in electrohysterogram (EHG) signals as a means to evaluate the synchronization of uterine contractions. Several studies have pointed out that the quality of signal processing – and hence the interpretation of measurement results – is affected significantly by the choice of measurement technique and the presence of non-stationary frequency content in EHG signals. To our knowledge, the effect of time variance on the quality of EHG signal processing has never been fully investigated. How best to process EHG signals with the goal of distinguishing labor-induced contractions from their harmless, pre-labor cousins, remains an open question.
Our methodology is based on three pillars. The first consists of a new method for EHG preprocessing in which we apply a second-order Butterworth filter to retain only the EHG fast-wave, low-frequency band (FWL), then use a bivariate piecewise stationary pre-segmentation (bPSP) algorithm to segment the EHG signal into stationary parts. The second pillar addresses the estimation of connectivity and directionality using three methods: nonlinear correlation coefficient (h²), general synchronization (H), and Granger causality (GC). The third pillar is related to signal classification and discrimination between pregnancy and labor using receiver operating curves (ROC) and connectivity and direction maps. For this purpose, we analyze the impact of four factors on data processing efficiency: i) method of connectivity detection, ii) effect of piecewise stationary segmentation preprocessing, iii) retained frequency content and iv) electrode configuration used for EHG recording (bipolar vs. unipolar).
Our results show that piecewise signal segmentation and filtering considerably improves classification performance and statistical significance for some connectivity methods, in particular the h². To this end we propose a new approach (detailed below) for h² called Filtered-Windowed (FW) h² that better highlights the differences between pregnancy and labor in the connectivity matrix and directionality maps.
This is the first comparative study of the effects of multiple processing factors on connectivity measurement efficiency. Our results indicate that appropriate preprocessing can improve the differentiation of pregnancy and labor-induced contraction signals and may lead to innovative applications in the prevention of preterm labor.

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: Cite this article as: Euliano TY, Marossero D, Nguyen MT, et al. Spatiotemporal electrohysterography patterns in normal and arrested labor. Am J Obstet Gynecol 2009;200:54.e1-54.e7.

: Reprints not available from authors.

: This material is based upon work supported by the National Science Foundation under Grant No. DMI-0239060.

: Dr N. R. Euliano is president, and Ms Marossero and Mr Nguyen are employees of Convergent Engineering. Drs T. Y. Euliano and N. R. Euliano, Ms Marossero, and Dr Principe are listed on patents filed for some of the technology described in this paper.

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ResearchObstetricsSpatiotemporal electrohysterography patterns in normal and arrested labor

Objective

Study Design

Results

Conclusion

Section snippets

Materials and Methods

Results

Comment

Acknowledgments

Obstet Gynecol

Obstet Gynecol

Obstet Gynecol

Med Hypotheses

Am J Obstet Gynecol

Med Eng Physics

Am J Obstet Gynecol

Int J Gynecol Obstet

Am J Obstet Gynecol

Am J Obstet Gynecol

Obstet Gynecol

Eur J Obstet Gynecol Reprod Biol

Births: final data for 2004National vital statistics reports 55(1)

Research
Obstetrics
Spatiotemporal electrohysterography patterns in normal and arrested labor