Multi-channel electrohysterography enabled uterine contraction characterization and its effect in delivery assessment.

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<10-5) 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 ≤ 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.

Assessment of uterine contractions in labor and delivery.

Normal labor and delivery are dependent on the presence of regular and effective contractions of the uterine myometrium. The mechanisms responsible for the initiation and maintenance of adequate and synchronized uterine activity that are necessary for labor and delivery result from a complex interplay of hormonal, mechanical, and electrical factors that have not yet been fully elucidated. Monitoring uterine activity during term labor and in suspected preterm labor is an important component of obstetrical care because cases of inadequate and excessive uterine activity can be associated with substantial maternal and neonatal morbidity and mortality. Inadequate labor progress is a common challenge encountered in intrapartum care, with labor dystocia being the most common indication for cesarean deliveries performed during labor. Hereafter, an accurate assessment of uterine activity during labor can assist in the management of protracted labor by diagnosing inadequate uterine activity and facilitating the titration of uterotonic medications before a trial of labor is prematurely terminated. Conversely, the ability to diagnose unwanted or excessive uterine activity is also critical in cases of threatened preterm labor, tachysystole, or patients undergoing a trial of labor after cesarean delivery. Knowledge of uterine activity in these cases may guide the use of tocolytic medications or raise suspicion of uterine rupture. Current diagnostic capabilities are less than optimal, hindering the medical management of term and preterm labor. Currently, different methods exist for evaluating uterine activity during labor, including manual palpation, external tocodynamometry, intrauterine pressure monitoring, and electrical uterine myometrial activity tracing. Legacy uterine monitoring techniques have advantages and limitations. External tocodynamometry is the most widespread tool in clinical use owing to its noninvasive nature and its ability to time contractions against the fetal heart rate monitor. However, it does not provide information regarding the strength of uterine contractions and is limited by signal loss with maternal movements. Conversely, the intrauterine pressure catheter quantifies the strength of uterine contractions; however, its use is limited by its invasiveness, risk for complications, and limited additive value in all but few clinical scenarios. New monitoring methods are being used, such as electrical uterine monitoring, which is noninvasive and does not require ruptured membranes. Electrical uterine monitoring has yet to be incorporated into common clinical practice because of lack of access to this technology, its high cost, and the need for appropriate training of clinical staff. Further work needs to be done to increase the accessibility and implementation of this technique by experts, and further research is needed to implement new practical and useful methods. This review describes current clinical tools for uterine activity assessment during labor and discusses their advantages and shortcomings. The review also summarizes current knowledge regarding novel technologies for monitoring uterine contractions that are not yet in widespread use, but are promising and could help improve our understanding of the physiology of labor, delivery, and preterm labor, and ultimately enhance patient care.

Uterine slow wave: directionality and changes with imminent delivery.

Objective.The slow wave (SW) of the electrohysterogram (EHG) may contain relevant information on the electrophysiological condition of the uterus throughout pregnancy and labor. Our aim was to assess differences in the SW as regards the imminence of labor and the directionality of uterine myoelectrical activity.Approach. The SW of the EHG was extracted from the signals of the Icelandic 16-electrode EHG database in the bandwidth [5, 30] mHz and its power, spectral content, complexity and synchronization between the horizontal (X) and vertical (Y) directions were characterized by the root mean square (RMS), dominant frequency (domF), sample entropy (SampEn) and maximum cross-correlation (CCmax) of the signals, respectively. Significant differences between parameters at time-to-delivery (TTD) ≤7 versus >7 days and between the horizontal versus vertical directions were assessed.Main results.The SW power significantly increased in both directions as labor approached (TTD ≤ 7d versus >7d (mean±SD):RMSx = 0.12 ± 0.10 versus 0.08 ± 0.06 mV;RMSy = 0.12 ± 0.09 versus 0.08 ± 0.05 mV), as well as the dominant frequency in the horizontal direction (domFx= 9.1 ± 1.3 versus 8.5 ± 1.2mHz) and the synchronization between both directions (CCmax= 0.44 ± 0.16 versus 0.36 ± 0.14). Furthermore, its complexity decreased in the vertical direction (SampEny= 6.13·10-2 ± 8.7·10-3versus 6.50·10-2 ± 8.3·10-3), suggesting a higher cell-to-cell electrical coupling. Whereas there were no differences between the SW features in both directions in the general population, statistically significant differences were obtained between them in individuals in many cases.Significance.Our results suggest that the SW of the EHG is related to bioelectrical events in the uterus and could provide objective information to clinicians in challenging obstetric scenarios.

Recognition of uterine contractions with electrohysterogram and exploring the best electrode combination.

BACKGROUND: 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. OBJECTIVE: This paper aims to recognize UCs with electrohysterogram (EHG) and find the best electrode combination with fewer electrodes. METHODS: 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. RESULTS: 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. CONCLUSIONS: The optimal electrode combination with fewer electrodes was confirmed to improve the clinical application for long-term monitoring of UCs.

Novel uterine contraction monitoring to enable remote, self-administered nonstress testing.

BACKGROUND: The serial fetal monitoring recommended for women with high-risk pregnancies places a substantial burden on the patient, often disproportionately affecting underprivileged and rural populations. A telehealth solution that can empower pregnant women to obtain recommended fetal surveillance from the comfort of their own home has the potential to promote health equity and improve outcomes. We have previously validated a novel, wireless pregnancy monitor that can remotely capture fetal and maternal heart rates. However, such a device must also detect uterine contractions if it is to be used to robustly conduct remote nonstress tests. OBJECTIVE: This study aimed to describe and validate a novel algorithm that uses biopotential and acoustic signals to noninvasively detect uterine contractions via a wireless pregnancy monitor. STUDY DESIGN: A prospective, open-label, 2-center study evaluated simultaneous detection of uterine contractions by the wireless pregnancy monitor and an intrauterine pressure catheter in women carrying singleton pregnancies at ≥32 0/7 weeks' gestation who were in the first stage of labor (ClinicalTrials.gov Identifier: NCT03889405). The study consisted of a training phase and a validation phase. Simultaneous recordings from each device were passively acquired for 30 to 60 minutes. In a subset of the monitoring sessions in the validation phase, tocodynamometry was also deployed. Three maternal-fetal medicine specialists, blinded to the data source, identified and marked contractions in all modalities. The positive agreement and false-positive rates of both the wireless monitor and tocodynamometry were calculated and compared with that of the intrauterine pressure catheter. RESULTS: A total of 118 participants were included, 40 in the training phase and 78 in the validation phase (of which 39 of 78 participants were monitored simultaneously by all 3 devices) at a mean gestational age of 38.6 weeks. In the training phase, the positive agreement for the wireless monitor was 88.4% (1440 of 1692 contractions), with a false-positive rate of 15.3% (260/1700). In the validation phase, using the refined and finalized algorithm, the positive agreement for the wireless pregnancy monitor was 84.8% (2722/3210), with a false-positive rate of 24.8% (897/3619). For the subgroup who were monitored only with the wireless monitor and intrauterine pressure catheter, the positive agreement was 89.0% (1191/1338), with a similar false-positive rate of 25.4% (406/1597). For the subgroup monitored by all 3 devices, the positive agreement for the wireless monitor was significantly better than for tocodynamometry (P<.0001), whereas the false-positive rate was significantly higher (P<.0001). Unlike tocodynamometry, whose positive agreement was significantly reduced in the group with obesity compared with the group with normal weight (P=.024), the positive agreement of the wireless monitor did not vary across the body mass index groups. CONCLUSION: This novel method to noninvasively monitor uterine activity, via a wireless pregnancy monitoring device designed for self-administration at home, was more accurate than the commonly used tocodynamometry and unaffected by body mass index. Together with the previously reported remote fetal heart rate monitoring capabilities, this added ability to detect uterine contractions has created a complete telehealth solution for remote administration of nonstress tests.

Métodos anticonceptivos elegidos por mujeres después de aborto en un hospital público de Honduras / Contraceptive methods chosen by women after abortion in a public hospital in Honduras

Antecedentes: La tasa de embarazos no planeados en Latinoamérica está entre las más altas del mundo. Las adoles- centes están entre los grupos más vulnerables para embarazos no planeados con porcentajes de 32% a 45%. Objetivo: Describir los factores asociados a la elección de un anticonceptivo por las mujeres después de un aborto, en el Hospital Dr. Roberto Suazo Córdova, La Paz, Honduras, en el periodo de julio 2017 a junio 2019. Método: Estudio retrospectivo descriptivo. Los datos fueron obtenidos usando el Sistema Informático Perinatal Aborto (SIP Aborto) en la versión SIP 4.16. Resultados: El 50.0% (67/134) de las adolescentes y 50.1% (281/550) de las mayores de 19 años eligieron un anticonceptivo postaborto. El inicio del anticonceptivo se relacionó con antecedente de aborto (p=0.006). Uso previo de anticonceptivos (p=0.007). Los anticonceptivos más elegidos fueron: Acetato de medroxiprogesterona, anticonceptivos orales combinados y condón. La elección del anticonceptivo se relacionó con evacuación instrumental del aborto (p=0.022) en adolescentes y (p=0.000) en mayores de 19 años. Se eligieron menos los mé- todos reversibles de acción prolongada. Discusión: La elección anticonceptiva postaborto fue baja. El inicio de anticonceptivos se relacionó con antecedente de aborto, uso previo de anticoncepti- vos y evacuación instrumental. Los anticonceptivos más elegidos fueron los temporales de acción corta y los menos elegidos, los temporales de acción prolongada. Se debe fortalecer el acceso a información, mejorar la consejería, garantizar acceso y disponibili- dad de anticonceptivos sobre todo de acción prolongada para ase- gurar el apego al método anticonceptivo...(AU)

Non-invasive fetal electrocardiography, electrohysterography and speckle-tracking echocardiography in the second trimester: study protocol of a longitudinal prospective cohort study (BEATS-study).

BACKGROUND: Worldwide, hypertensive disorders of pregnancy (HDP), fetal growth restriction (FGR) and preterm birth remain the leading causes of maternal and fetal pregnancy-related mortality and (long-term) morbidity. Fetal cardiac deformation changes can be the first sign of placental dysfunction, which is associated with HDP, FGR and preterm birth. In addition, preterm birth is likely associated with changes in electrical activity across the uterine muscle. Therefore, fetal cardiac function and uterine activity can be used for the early detection of these complications in pregnancy. Fetal cardiac function and uterine activity can be assessed by two-dimensional speckle-tracking echocardiography (2D-STE), non-invasive fetal electrocardiography (NI-fECG), and electrohysterography (EHG). This study aims to generate reference values for 2D-STE, NI-fECG and EHG parameters during the second trimester of pregnancy and to investigate the diagnostic potential of these parameters in the early detection of HDP, FGR and preterm birth. METHODS: In this longitudinal prospective cohort study, eligible women will be recruited from a tertiary care hospital and a primary midwifery practice. In total, 594 initially healthy pregnant women with an uncomplicated singleton pregnancy will be included. Recordings of NI-fECG and EHG will be made weekly from 22 until 28 weeks of gestation and 2D-STE measurements will be performed 4-weekly at 16, 20, 24 and 28 weeks gestational age. Retrospectively, pregnancies complicated with pregnancy-related diseases will be excluded from the cohort. Reference values for 2D-STE, NI-fECG and EHG parameters will be assessed in uncomplicated pregnancies. After, 2D-STE, NI-fCG and EHG parameters measured during gestation in complicated pregnancies will be compared with these reference values. DISCUSSION: This will be the a large prospective study investigating new technologies that could potentially have a high impact on antepartum fetal monitoring. TRIAL REGISTRATION: Registered on 26 March 2020 in the Dutch Trial Register (NL8769) via https://www.trialregister.nl/trials and registered on 21 October 2020 to the Central Committee on Research Involving Human Subjects (NL73607.015.20) via https://www.toetsingonline.nl/to/ccmo_search.nsf/Searchform?OpenForm .

[Electrohysterography, a promising alternative for uterine monitoring: 5 years later]. / Elektrohysterografie veelbelovend alternatief voor weeënregistratie.

Electrohysterography monitors the electrical activity of the uterine muscle through electrodes on the maternal abdominal wall. It is a non-invasive method for uterine contraction monitoring and has a strong correlation with the invasive intra-uterine pressure catheter. A prospective validation study showed a significant higher sensitivity of electrohysterography compared to external tocodynamometry for uterine contraction detection (p-value < 0.001). Moreover, the sensitivity of electrohysterography appears to be less affected by maternal obesity compared to external tocodynamometry. A clinical pilotstudy comparing electrohysterography and external tocodynamometry during labor, showed no negative effect of electrohysterography on labor outcomes. Recently, technical improvements have been made and electrohysterography has become available in an adhesive electrode patch together with fetal and maternal electrocardiography. Therefore, we expect a successful implementation of electrohysterography in the near future.

Knowledge on intrapartum care practices among skilled birth attendants in Cambodia-a cross-sectional study.

BACKGROUND: Delivery is a critical moment for pregnant women and babies, and careful monitoring is essential throughout the delivery process. The partograph is a useful tool for monitoring and assessing labour progress as well as maternal and foetal conditions; however, it is often used inaccurately or inappropriately. A gap between practices and evidence-based guidelines has been reported in Cambodia, perhaps due to a lack of evidence-based knowledge in maternity care. This study aims to address to what extent skilled birth attendants in the first-line health services in Cambodia have knowledge on the management of normal delivery, and what factors are associated with their level of knowledge. METHODS: Midwives and nurses were recruited working in maternity in first-line public health facilities in Phnom Penh municipality, Kampong Cham and Svay Rieng provinces. Two self-administered questionnaires were applied. The first consisted of three sections with questions on monitoring aspects of the partograph: progress of labour, foetal, and maternal conditions. The second consisted of questions on diagnostic criteria, normal ranges, and standard intervals of monitoring during labour. A multiple linear regression analysis was performed to identify relationships between characteristics of the participants and the questionnaire scores. RESULTS: Of 542 eligible midwives and nurses, 523 (96%) participated. The overall mean score was 58%. Only 3% got scores of more than 90%. Multivariate analysis revealed that 'Kampong Cham province', 'younger age', and 'higher qualification' were significantly associated with higher scores. Previous training experience was not associated with the score. Substantial proportions of misclassification of monitoring items during labour were found; for example, 61% answered uterine contraction as a foetal condition, and 44% answered foetal head descent and 26% answered foetal heart rate as a maternal condition. CONCLUSION: This study found that knowledge was low on delivery management among skilled birth attendants. Previous training experience did not influence the knowledge level. A lack of understanding of physiology and anatomy was implied. Further experimental approaches should be attempted to improve the knowledge and quality of maternity services in Cambodia.

Pregnancy and childbirth are natural phenomena, but sometimes have risk for mothers and babies. Therefore, childbirth should be carefully and continuously monitored by the health care professional. The 'partograph' is a useful tool that defines three monitoring aspects of the delivery progress, and conditions of the mother and intrauterine baby. However, it is often used inaccurately or inappropriately in low- and middle-income countries. We hypothesised that health professionals who assist childbirth cannot effectively monitor delivery conditions because their knowledge is insufficient. Therefore, we evaluated the knowledge on monitoring the process of childbirth and explored factors which affect the level of knowledge among health care providers in Cambodia.Midwives and nurses were targeted in this study who deal with normal deliveries in the capital city and two provinces. The questionnaire was designed to evaluate if their knowledge on three monitoring aspects is accurate.Of 542 eligible personnel, 523 (96%) participated. The mean score was 58%. Only 3% got scores of more than 90%. According to the statistical analysis, 'working in Kampong Cham province', 'younger age', and 'higher qualification' were significantly associated with higher scores. Previous training experience was not associated with the score.This study found that basic knowledge was low on delivery management among health care providers. We suspect that a deficiency of basic medical knowledge, such as physiology and anatomy, causes the lack of knowledge on the childbirth process. Further intervention should be attempted to improve the knowledge and quality of maternity services in Cambodia.

Using shear wave elastography to assess uterine tonicity after vaginal delivery.

This study aims to evaluate the feasibility and clinical interest of shear wave elastography, by quantitatively estimating the baseline stiffness of the myometrium before and after placental expulsion. We conducted a prospective cohort study of women at term, without known risk factors for postpartum hemorrhage, who gave birth via spontaneous labor in our tertiary center. Myometrium tonicity was evaluated based on measurements of shear wave speed (SWS) in the anterior uterine corpus. All data points were collected by a single operator. Measurements were carried out at three different time points: after fetal delivery (T1), after placental delivery (T2) and 30 min after placental delivery (T3). Our primary objective was to assess the feasibility of this new imaging technique. Ten valid SWS measurements obtained at each of the three different time points were considered as a positive primary outcome. Our secondary objectives were to evaluate the difference in median myometrial shear wave velocity between each time point, as well as to determine the correlation between myometrial shear wave velocity and patients' characteristics. 38 women were recruited during the study period, of whom 34 met the study criteria. 1017 SWS measurements were obtained. The median time to perform measurements was 16 s for one value, and 2 min 56 s for ten. For 11 women (32%) it was not possible to achieve ten SWS at T1 as placental expulsion immediately followed the birth of the newborn. One patient experienced placental retention and only measurements at T1 were performed. For all other patients, we were successfully able to obtain all measures as intended. There was no difference in the mean shear wave speed between the three time points. After adjustments for confounders, we observed a significant correlation for total blood loss (correlation coefficient = - 0.26, p < 0.001, units of oxytocin (correlation coefficient = - 0.34, p = 0.03), and newborn weight (correlation coefficient = - 0.08, p = 0.001). It is feasible to assess uterine tonicity by shear wave imaging, after placental expulsion. We did not observe a variance in uterine tonicity between the three time points. Women who had higher blood loss, received more units of oxytocin and/or those with newborns of a higher weight exhibited lower shear wave speed measures.

Noninvasive monitoring of uterine electrical activity among patients with obesity: a new external monitoring device.

BACKGROUND: Tocodynamometry is a common, noninvasive tool used to measure contraction frequency; however, its utility is often limited in patients with obesity. An intrauterine pressure catheter provides a more accurate measurement of uterine contractions but requires ruptured membranes, limiting its utility during early latent labor. Electrical uterine myography has shown promise as a noninvasive contraction monitor with efficacy similar to that of the intrauterine pressure catheter; however, its efficacy has not been widely studied in the obese population. OBJECTIVE: This study aimed to validate the accuracy of electrical uterine myography by comparing it with tocodynamometry and intrauterine pressure catheters among laboring patients with obesity. STUDY DESIGN: This was a prospective observational study from February 2017 to April 2018 of patients with obesity, aged 18 years or older, who were admitted to the labor unit with viable singleton pregnancies and no contraindications for electromyography. Patients were monitored simultaneously with electrical myography and tocodynamometry or intrauterine catheter for more than 30 minutes. Two blinded obstetricians reviewed the tracings. The outcomes of interest were continuous and interpretable tracing, number of contractions, and timing and duration of contractions, interpreted as point estimates and associated 95% confidence intervals. RESULTS: A total of 110 patients were enrolled (65 tocodynamometry, 55 intrauterine catheter). Electrical myography was significantly more interpretable during a 30-minute tracing (P=.001) and detected 39% more contractions than tocodynamometry (P<.0001; 95% confidence interval, 23%-57%), whereas there was no difference in the interpretability of tracings or number of contractions between electrical myography and an intrauterine catheter (P=.16; 95% confidence interval, -0.19 to 1.19). Patients who underwent simultaneous monitoring preferred the electrical myography device over tocodynamometry. CONCLUSION: Electrical uterine myography is superior to tocodynamometry in the detection of intrapartum uterine contraction monitoring and comparable with internal contraction monitoring.

The assessment of selected parameters of bioelectric and mechanical activity of the uterus during pharmacologic treatment of threatening preterm delivery.

OBJECTIVES: To analyze and compare the bioelectric and mechanical activity of the uterus in pregnant women with threatening preterm delivery treated with tocolysis. Additionally, auxiliary parameters of the bioelectric signal, as registered by electrohysterography and characteristic only for this method, were measured and analyzed. MATERIAL AND METHODS: Forty-five women with pregnancies from 24 to 36 weeks of gestation with typical clinical symptoms of threatening preterm delivery were given tocolytic therapy. Registration and analysis of bioelectric activity with electrohysterography was performed simultaneously with registration and analysis of mechanical activity with tocography. RESULTS: After administration of tocolytic treatment, the presence of bioelectric activity was accompanied by the lack of or minimal occurrence of mechanical activity. All parameters of contraction recorded by electrohysterography had significantly greater values than those recorded by tocography. CONCLUSIONS: Measurement of bioelectric activity is more sensitive than measurement of mechanical activity of the uterus. Elevated bioelectric activity of the uterine muscle was observed despite the use of tocolysis, a lack of symptoms of threatening preterm delivery, as well as a lack of contraction in tocography. The presence of bioelectric activity may precede the occurrence of mechanical activity of the uterus, but further research is required on larger groups of patients.

Performance comparison of coupling-evaluation methods in discriminating between pregnancy and labor EHG signals.

BACKGROUND: 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. METHOD: 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). RESULTS: 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. CONCLUSIONS: 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.

Internal fetal and uterine monitoring in obese patients and maternal obstetrical outcomes.

BACKGROUND: The maternal habitus in the setting of obesity makes external monitoring of the fetal heart rate and contractions suboptimal, and internal monitors may be utilized more often in this population. Obesity is a risk factor for obstetrical infectious complications, but it is unknown whether the use of internal monitors in this population is associated with additional risks. OBJECTIVE: This study aimed to investigate the association between the use of an intrauterine pressure catheter and a fetal scalp electrode and maternal infectious morbidity among women with obesity. STUDY DESIGN: This secondary analysis of a prospective cohort study included women with singleton gestations admitted for labor at ≥37 weeks' gestation at a tertiary care institution from 2010 to 2014. Obesity was defined as a body mass index of ≥30 kg/m2. The primary outcome was a composite maternal infectious morbidity, which included peripartum maternal fever, chorioamnionitis, and endomyometritis. Secondary outcomes were cesarean delivery and individual components of the maternal infectious composite. Multivariable logistic regression was used to compare the rates of infectious maternal morbidity, cesarean delivery, or operative vaginal delivery between patients with and without internal monitors, while adjusting for the confounders. An interaction term was included in the logistic regression models to test whether the relationship between the internal monitors and cesarean delivery or infectious morbidity was modified by the presence or absence of obesity. RESULTS: Of the 8482 women who met the inclusion criteria for the study, 4727 (55.7%) had obesity and 3755 (44.3%) did not have obesity. The women with obesity were more likely to have internal monitors placed during labor than those without obesity (65.4% vs 50.5%; P<.001). The use of internal monitors was associated with an increased risk for the composite maternal infectious morbidity (9.9% vs 4.1%; P<.01 and adjusted odds ratio, 2.08; 95% confidence interval, 1.70-2.55). Women with obesity had a weaker association between the use of internal monitors and maternal infectious morbidity than women without obesity (P value for interaction of .02). The incidence of cesarean delivery was also significantly higher among women who had internal monitors placed during their labor course (adjusted odds ratio, 2.84; 95% confidence interval, 2.46-3.28), and this interaction was not modified by obesity. CONCLUSION: Although a higher proportion of women with obesity have internal monitors placed during their labor course, they are not more susceptible to maternal infectious morbidity as a result of internal monitor use. Providers should not limit the necessary internal monitor use in women with obesity on the basis of concerns for maternal infectious morbidity.

M-mode Ultrasound Scan as a Potential Alternative Technique for Monitoring Uterine Contractions in Obese Patients.

We investigate motion mode (M-mode) ultrasound scan as a potential non-invasive uterine monitoring technique and compare its contraction characteristics with external tocodynamometry (TOCO). This prospective diagnostic accuracy study included 39 term pregnant woman in active spontaneous labor. M-mode and TOCO were simultaneously performed and uterine contraction characteristics and consistency were compared quantitatively and visually. The results identified a 71.5% ± 35.3% uterine wall thickening during uterine contractions on M-mode. Uterine monitoring with M-mode had a consistency rate of 88.7% ± 6.9% with conventional TOCO method. During 20-min monitoring, the number of detected contractions was significantly higher (p < 0.001) in M-mode (8.2 ± 1.2) than TOCO (7.4 ± 1.5). As for the mean value of the duration of a contraction (seconds), it was significantly shorter (p < 0.001) in M-mode (38.5 ± 3.5) than TOCO (49.2 ± 4.1). For M-mode, the number of detected contractions had a negative but insignificant correlation with the body mass index (BMI) (r = - 0.25 [- 0.52, 0.07], p = 0.127) and the subcutaneous tissue thickness (STT) (r = - 0.21 [- 0.49, 0.11], p = 0.200). As for TOCO, the contractions had a negative and significant correlation with BMI (r = - 0.41 [- 0.64, - 0.11], p = 0.009) and negative and insignificant correlation with STT (r = - 0.26 [- 0.54, 0.06], p = 0.104). The evidence suggests that contraction detection with M-mode is a promising non-invasive technique for uterine monitoring. The preliminary analysis finds that contraction detection is not affected by BMI or STT. With future sensitivity studies, and improvements in image-processing and software technologies, the proposed technique promises to be a viable alternative to existing techniques, especially for obese patients.

Automatic recognition of uterine contractions with electrohysterogram signals based on the zero-crossing rate.

Uterine contraction (UC) is an essential clinical indicator in the progress of labour and delivery. Electrohysterogram (EHG) signals recorded on the abdomen of pregnant women reflect the uterine electrical activity. This study proposes a novel algorithm for automatic recognition of UCs with EHG signals to improve the accuracy of detecting UCs. EHG signals by electrodes, the tension of the abdominal wall by tocodynamometry (TOCO) and maternal perception were recorded simultaneously in 54 pregnant women. The zero-crossing rate (ZCR) of the EHG signal and its power were calculated to modulate the raw EHG signal and highlight the EHG bursts. Then the envelope was extracted from the modulated EHG for UC recognition. Besides, UC was also detected by the conventional TOCO signal. Taking maternal perception as a reference, the UCs recognized by EHG and TOCO were evaluated with the sensitivity, positive predictive value (PPV), and UC parameters. The results show that the sensitivity and PPV are 87.8% and 93.18% for EHG, and 84.04% and 90.89% for TOCO. EHG detected a larger number of UCs than TOCO, which is closer to maternal perception. The duration and frequency of UC obtained from EHG and TOCO were not significantly different (p > 0.05). In conclusion, the proposed UC recognition algorithm has high accuracy and simple calculation which could be used for real-time analysis of EHG signals and long-term monitoring of UCs.

Clinical evaluation of labor: an evidence- and experience-based approach.

During labor mother and fetus are evaluated at intervals to assess their well-being and determine how the labor is progressing. These assessments require skillful physical diagnosis and the ability to translate the acquired information into meaningful prognostic decision-making. We describe a coordinated approach to the assessment of labor. Graphing of serial measurements of cervical dilatation and fetal station creates "labor curves," which provide diagnostic and prognostic information. Based on these curves we recognize nine discrete labor abnormalities. Many may be related to insufficient or disordered contractile mechanisms. Several factors are strongly associated with development of labor disorders, including cephalopelvic disproportion, excess analgesia, fetal malpositions, intrauterine infection, and maternal obesity. Clinical cephalopelvimetry involves assessing pelvic traits and predicting their effects on labor. These observations must be integrated with information derived from the labor curves. Exogenous oxytocin is widely used. It has a high therapeutic index, but is easily misused. Oxytocin treatment should be restricted to situations in which its potential benefits clearly outweigh its risks. This requires there be a documented labor dysfunction or a legitimate medical reason to shorten the labor. Normal labor and delivery pose little risk to a healthy fetus; but dysfunctional labors, especially if stimulated excessively by oxytocin or terminated by complex operative vaginal delivery, have the potential for considerable harm. Conscientiously implemented, the approach to the evaluation of labor outlined in this review will result in a reasonable cesarean rate and minimize risks that may accrue from the labor and delivery process.

Potential use of electrohysterography in obstetrics: a review article.

Monitoring the uterine contraction during pregnancy is necessary to monitor labor progress, fetal and maternal well-being, and uterine activity. The aim of this review was to evaluate the performance of electrohysterography and to analyze the nature of uterine contraction. A search was undertaken using PubMed, Embase, and ClinicalTrials.gov database from 1 January 1950 to 1 November 2018. Search terms include: "Uterine" or "Uterus" or "Labor" or "Labour" and "electrical activity" or "electrohysterogram" or "electrohysterograph". Reviewing the literature, electrohysterography showed a higher sensitivity for uterine contraction detection and was independent of body mass index, abdominal wall thickness, or maternal position enabling monitoring obese patients as well. Electrohysterography can enhance uterine monitoring throughout labor because of its noninvasiveness, adhesive properties, and reduced obesity sensitiveness. Electrohysterography should be available to safely improve intrapartum monitoring instead of the invasive intrauterine pressure catheter.

Qualitative assessment of interpretability and observer agreement of three uterine monitoring techniques.

OBJECTIVE: The aim of this research was to assess the quality and inter- and intra-observer agreement of tracings obtained by three different techniques for uterine contraction monitoring: the external tocodynamometer (TOCO), the intrauterine pressure catheter (IUPC) and a recently introduced method based on electrohysterography (EHG). STUDY DESIGN: We included 150 uterine activity registrations from a previous prospective observational study (W3 study), conducted at Máxima Medical Centre in Veldhoven, the Netherlands. Term singleton pregnant women were simultaneously monitored with TOCO, IUPC and EHG during labor. Six clinicians, blinded to the source (TOCO, IUPC, or EHG) and subject, evaluated all tracings that were subsequently presented in random order. They annotated contractions and assigned each tracing a score for interpretability of 2 (good), 1 (moderate) or 0 (poor). To evaluate inter-observer agreement, we calculated kappa values for the qualitative assessment, and intraclass correlation coefficients (ICC) for the number of contractions annotated by clinicians. Four clinicians repeated this procedure to evaluate intra-observer agreement. RESULTS: IUPC tracings received the highest quality rating, with a mean score of 1.95, followed by a mean score of 1.60 for EHG and 0.80 for TOCO (p < 0.05). Mean weighted kappa values were 0.63 for TOCO and 0.45 for EHG. The average number of contractions that was picked up by clinicians was 59.8 for the intrauterine pressure catheter, 49.8 for EHG and 26.4 for TOCO. The ICC of the intrauterine pressure catheter was significantly higher than the external methods, regarding both inter- and intra-observer agreement (0.98 and 0.99 respectively). CONCLUSION: IUPC recordings scored best regarding quality, inter- and intra-observer agreement. However, due to safety issues, in many countries this technique is not used anymore. The quality of TOCO was rated as poor and many contractions were missed as compared to the gold standard. From a clinical interpretational point of view, EHG is favorable to TOCO. EHG recordings were assigned higher quality scores, but with less agreement between clinicians. An explanation could be that EHG is a relatively new technique, while IUPC and the TOCO are being used for decades. Building experience with EHG (training) is therefore recommended.