External recordings of the electrohysterogram (EHG) can provide new knowledge on uterine electrical activity associated with contractions. Better understanding of the mechanisms underlying labor can ...contribute to preventing preterm birth which is the main cause of mortality and morbidity in newborns. Promising results using the EHG for labor prediction and other uses in obstetric care are the drivers of this work. This paper presents a database of 122 4-by-4 electrode EHG recordings performed on 45 pregnant women using a standardized recording protocol and a placement guide system. The recordings were performed in Iceland between 2008 and 2010. Of the 45 participants, 32 were measured repeatedly during the same pregnancy and participated in two to seven recordings. Recordings were performed in the third trimester (112 recordings) and during labor (10 recordings). The database includes simultaneously recorded tocographs, annotations of events and obstetric information on participants. The publication of this database enables independent and novel analysis of multi-electrode EHG by the researchers in the field and hopefully development towards new life-saving technology.
Measurement of cervical dilation is one of the major indicators of labor progression. At present, the criterion standard for this evaluation is digital examination, which results are sometimes ...inaccurate and extremely dependent on the subject (ie, obstetrician or midwife) experience.
In this systematic and meta-analysis review, the authors have gathered the vast majority of the instruments used for measuring cervical dilation and their clinical application; main features, potentialities, and the most significant constraints are underlined for each device.
Three of the most popular databases (ie, Web of Science, PubMed, and ClinicalTrials.gov) were used to identify all available cervimeters, by using single or combinations of the following keywords: "cervical," "dilation or dilatation," "cervimetry," "cervix," "uterine," "measurement," "labour or labor," "birth," and "monitoring." Only articles describing the design or a specific clinical application of an instrument for cervical dilation measurement during labor were selected.
Twenty-five articles were deeply investigated by classifying them in 4 different homogenous groups on the basis of the method proposed for measuring cervical dilation. Suitable devices have not been realized yet, and this is the reason why nowadays the gynecologist/obstetrician still evaluates labor progression by digital examination.
Based on a critical analysis of the selected devices, ultrasound seems to be the most promising technology for future cervimetry realization; ultrasound is accurate in distance measurement, and the behind technology can be miniaturized. However, additional studies are necessary for optimizing the technology and developing an optimal solution.
Resumen ANTECEDENTES: El análisis del registro de superficie de la actividad mioeléctrica uterina, o electrohisterograma, es uno de los marcadores biofísicos más prometedores para evaluar las ...contracciones y el estado electrofisiológico del útero. A pesar de las evidencias derivadas de la información clínica que proporciona el análisis electrohisterográfico, hasta la fecha no se ha logrado el esfuerzo significativo para introducir esta técnica en la práctica médica. OBJETIVO: Mostrar la evidencia disponible acerca de la utilidad de la electrohisterografía como técnica alternativa para la monitorización de la actividad uterina en el ámbito clínico. METODOLOGÍA: Búsqueda bibliográfica en las bases de datos de PubMed, Google Scholar y Scopus, con las palabras clave: electrohysterogram, uterine electromyography y electrohysterography. RESULTADOS: Se seleccionaron 65 artículos originales, 5 de revisión y 1 capítulo de libro con metodología adecuada, claridad y relevancia clínica, enfocados en la aplicación clínica del electrohisterograma. CONCLUSIÓN: Las técnicas de monitoreo convencional de la actividad uterina tienen limitaciones para establecer, oportunamente, el diagnóstico de distocias durante el trabajo de parto. El análisis de registros electrohisterográficos permite explicar las alteraciones detectadas en la actividad eléctrica uterina, mediante el aporte de información del estado funcional, incluso predecir posibles complicaciones durante el trabajo de parto.
Highlights • Machine learning methods for medical labor induction is proposed. • A total of 33 predictive models using obstetrical data and electrophysiological parameters were developed and ...evaluated. • Electrophysiological parameters must be individually contextualized with patient obstetrical data (maternal clinical variables).
Preterm birth is a major public health problem in developed countries. In this context, we have conducted research into outpatient monitoring of uterine electrical activity in women at risk of ...preterm delivery. The objective of this preliminary study was to perform automated detection of uterine contractions (without human intervention or tocographic signal, TOCO) by processing the EHG recorded on the abdomen of pregnant women. The feasibility and accuracy of uterine contraction detection based on EHG processing were tested and compared to expert decision using external tocodynamometry (TOCO) .
The study protocol was approved by local Ethics Committees under numbers ID-RCB 2016-A00663-48 for France and VSN 02-0006-V2 for Iceland. Two populations of women were included (threatened preterm birth and labour) in order to test our system of recognition of the various types of uterine contractions. EHG signal acquisition was performed according to a standardized protocol to ensure optimal reproducibility of EHG recordings. A system of 18 Ag/AgCl surface electrodes was used by placing 16 recording electrodes between the woman's pubis and umbilicus according to a 4 × 4 matrix. TOCO was recorded simultaneously with EHG recording. EHG signals were analysed in real-time by calculation of the nonlinear correlation coefficient H
. A curve representing the number of correlated pairs of signals according to the value of H
calculated between bipolar signals was then plotted. High values of H
indicated the presence of an event that may correspond to a contraction. Two tests were performed after detection of an event (fusion and elimination of certain events) in order to increase the contraction detection rate.
The EHG database contained 51 recordings from pregnant women, with a total of 501 contractions previously labelled by analysis of the corresponding tocographic recording. The percentage recognitions obtained by application of the method based on coefficient H
was 100% with 782% of false alarms. Addition of fusion and elimination tests to the previously obtained detections allowed the false alarm rate to be divided by 8.5, while maintaining an excellent detection rate (96%).
These preliminary results appear to be encouraging for monitoring of uterine contractions by algorithm-based automated detection to process the electrohysterographic signal (EHG). This compact recording system, based on the use of surface electrodes attached to the skin, appears to be particularly suitable for outpatient monitoring of uterine contractions, possibly at home, allowing telemonitoring of pregnancies. One of the advantages of EHG processing is that useful information concerning contraction efficiency can be extracted from this signal, which is not possible with the TOCO signal.
Introduction
In a prospective study in a tertiary university hospital we wanted to determine whether uterine electromyography (EMG) can differentiate between the active and latent phase of labor.
...Material and methods
Thirty women presenting at ≥370/7 weeks of gestation with regular uterine contractions, intact membranes, and a Bishop score <6. EMG was recorded from the abdominal surface for 30 min. Latent phase was defined as no cervical change within at least 4 h. Student's t‐test was used for statistical analysis (p ≤ 0.05 significant). Diagnostic accuracy of EMG was determined by receiver operator characteristics (ROC) analysis. The integral of the amplitudes of the power density spectrum (PDS) corresponding to the PDS energy within the “bursts” of uterine EMG activity was compared between the active and latent labor groups.
Results
Seventeen (57%) women were found to be in the active phase of labor and 13 (43%) were in the latent phase. The EMG PDS integral was significantly higher (p = 0.02) in the active (mean 3.40 ± 0.82 μV) compared with the latent (mean 1.17 ± 0.33 μV) phase of labor. The PDS integral had an area under the ROC curve (AUC) of 0.80 to distinguish between active and latent phases of labor, compared with number of contractions on tocodynamometry (AUC = 0.79), and Bishop score (AUC = 0.78). The combination (sum) of PDS integral, tocodynamometry, and Bishop score predicted active phase of labor with an AUC of 0.90.
Conclusions
Adding uterine EMG measurements to the methods currently used in the clinics could improve the accuracy of diagnosing active labor.
The diagnosis of labor and effective prevention of preterm delivery are still among the most significant problems faced by obstetricians. Currently, there is no technique or method for objectively ...monitoring the uterus and assessing whether the organ has entered a state of increased activity that may indicate labor. Several studies have investigated a new, noninvasive technique to monitor uterine contractions: the electrohysterogram (EHG). Analysis of frequency-related parameters of the EHG may allow physiological uterine activity to be distinguished from uterine contractions that will lead to preterm delivery. However, although a variety of parameters and methodologies have been employed, they have not been objectively compared. The objective of this review, which was based on a systematic literature search using the Cochrane, PubMed, and EMBASE databases up to February 2008, was to determine whether frequency-related parameters of the EHG signal can reliably differentiate preterm contractions that will lead to preterm delivery from those that will not (in patients who will ultimately deliver at term) and to identify the most accurate parameter. Of all the different EHG parameters, both human and animal studies indicate that the power spectral density peak frequency may be the most predictive of true labor. The best parameter for predicting delivery is, therefore, related to the EHG spectral content shift, as calculated by Fourier transform, time-frequency, or Wavelet analysis. The incidence and extent to which shifts in uterine electrical spectral components occur, as the measurement-to-delivery interval decreases, imply that these changes might be used to predict preterm delivery. There is also promising data suggesting that a combination of the measured parameters, used as inputs to artificial neural network algorithms, may be more useful than individual ones for critically assessing uterine activity.
Obstetricians & Gynecologists, Family Physicians.
After completion of this article, the reader will be able to recall the physiology of uterine contractions leading to labor, summarize the limitations of tocodynamometry, and outline four different electrohysterogram parameters.
Objective: We aimed to evaluate the performance of a non-invasive EMG electrical uterine monitor (EUM) versus tocodynamometry (TOCO) by comparing both to internal uterine pressure catheter (IUPC).
...Study design: Prospective observational trial. Uterine activity was recorded continuously and simultaneously, in women during active term labor, with TOCO, EUM and IUPC. Uterine activity tracings were analyzed by three blinded physicians.
Results: Overall, 385 tracings from 43 women were analyzed. A similar rate of interpretable tracings between physicians was demonstrated for EUM (87%; 95% CI 80.9-92.7%) and IUPC (94.8%; 95% CI 83.4-96.3%), with a significantly lower rate for TOCO (67.5%; 95% CI 59.4-76.8%, p < 0.001). There is a significant difference in the contraction frequency for EUM versus IUPC (0.77 ± 2.3) compared to TOCO versus IUPC (−3.34 ± 4.97). There is a high variability between the timing of TOCO contractions as compared to IUPC (4.74 ± 10.03 seconds), while a gap of 8.46 ± 4.24 seconds was detected for EUM. The sensitivity, positive predictive value and false positive rate for individual contraction identification by TOCO and EUM are 54.0%, 84.4%, 15.6% and 94.2%, 87.6%, 12.4%, respectively.
Conclusion: EUM is efficient as IUPC for uterine activity assessment and both techniques are superior in comparison to external tocodynamometry. Our results support the use of non-invasive EMG technology to monitor uterine activity.
As an essential indicator of labour and delivery, uterine contraction (UC) can be detected by manual palpation, external tocodynamometry and internal uterine pressure catheter. However, these methods ...are not applicable for long-term monitoring.
This paper aims to recognize UCs with electrohysterogram (EHG) and find the best electrode combination with fewer electrodes.
112 EHG recordings were collected by our bespoke device in our study. Thirteen features were extracted from EHG segments of UC and non-UC. Four classifiers of the decision tree, support vector machine (SVM), artificial neural network, and convolutional neural network were established to identify UCs. The optimal classifier among them was determined by comparing their classification results. The optimal classifier was applied to evaluate all the possible electrode combinations with one to eight electrodes.
The results showed that SVM achieved the best classification capability. With SVM, the combination of electrodes on the right part of the uterine fundus and around the uterine body's median axis achieved the overall best performance.
The optimal electrode combination with fewer electrodes was confirmed to improve the clinical application for long-term monitoring of UCs.
maternal mortality represents the single greatest health disparity between high and low income countries. This inequity is especially felt in low income countries in sub Saharan Africa and Southeast ...Asia where 99% of the global burden of maternal death is borne. A goal of MDG 5 is to reduce maternal mortality and have a skilled attendant at every birth by 2015. A critical skill is ongoing intrapartum monitoring of labour progress and maternal/fetal well-being. The WHO partograph was designed to assess these parameters.
a retrospective review of charts (n=1,845) retrieved consecutively over a 2 month period in a tertiary teaching hospital in Ghana was conducted to assess the adequacy of partograph use by skilled birth attendants and the timeliness of action taken if the action line was crossed. WHO guidelines were implemented to assess the adequacy of partograph use and how this affected maternal neonatal outcomes. Further, the timeliness and type of action taken if action line was crossed was assessed.
partographs were adequately completed in accordance with WHO guidelines only 25.6% (472) of the time and some data appeared to be entered retrospectively. Partograph use was associated with less maternal blood loss and neonatal injuries. When the action line was crossed (464), timely action was taken only 48.7% of the time and was associated with less assisted delivery and a fewer low Apgar scores and NICU admissions.
when adequately used and timely interventions taken, the partograph was an effective tool. Feasibility of partograph use requires more scrutiny; particularly identification of minimum frequency for safe monitoring and key variables as well as a better understanding of why skilled attendants have not consistently ‘bought in’ to partograph use. Frontline workers need access to ongoing and current education and strategically placed algorhythims.
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