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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. [ABSTRACT FROM AUTHOR]

Introduction: The postpartum period can be complicated by hemorrhage, frequently caused by uterine atony. Electrohysterography, allowing continuous monitoring of uterine activity, may be a promising alternative for early detection of uterine atony, and thereby contribute to the prevention of postpartum hemorrhage. Associations between electrohysterographic parameters postpartum and total blood loss were studied., Methods: In this prospective explorative study, women were included with a vaginal delivery between 36 +0 and 42 +0 weeks of gestation. Linear regression analysis was used to describe the association between electrohysterographic parameters (i.e. area under the contraction curve (AUC) total (in arbitrary units), AUC from baseline (in arbitrary units), maximum amplitude (in arbitrary units) and baseline tone (in arbitrary units)) and total blood loss (in mL) during the first 30 min postpartum., Results: In total, 25 women were included for analysis, of whom three had postpartum hemorrhage. A moderate positive linear correlation was found between the logarithmically transformed total blood loss and the AUC total (r = 0.44, p = 0.03), AUC from baseline (r = 0.43, p = 0.03) and baseline tone (r = 0.43, p = 0.03). There was no significant linear correlation between the logarithmically transformed total blood loss and maximum amplitude. Explorative analysis revealed a significantly higher AUC total, AUC from baseline and baseline tone in women with postpartum hemorrhage compared to women without postpartum hemorrhage. (p = 0.02, p = 0.02 and p = 0.03, respectively)., Discussion: There is a moderate positive correlation between the logarithmically transformed total blood loss and the AUC total, AUC from baseline and baseline tone. Also, these parameters were all significantly higher in women with postpartum hemorrhage compared to women without postpartum hemorrhage., Competing Interests: Declaration of competing interest Author G.O. initiated the scientific research from which Nemo Healthcare B.V. (Veldhoven, the Netherlands) and the described NFMS device have originated. There are no financial relationships between Nemo Healthcare B.V. (Veldhoven, the Netherlands) and any of the authors., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: During labor, fetal heart rate (FHR) and uterine activity (UA) can be continuously monitored using Cardiotocography (CTG). This is the most widely adopted approach for electronic fetal monitoring in hospitals. Both FHR and UA recordings are evaluated by obstetricians for assessing fetal well-being. Due to the complex and noisy nature of these recordings, the evaluation by obstetricians suffers from high interobserver and intraobserver variability. Machine learning is a field that has seen unprecedented advances in the past two decades and many efforts have been made in computerized analysis of CTG using machine learning methods. However, in the literature, the focus is often only on FHR signals unlike in evaluations performed by obstetricians where the UA signals are also taken into account.Methods: Machine learning is a field that has seen unprecedented advances in the past two decades and many efforts have been made in computerized analysis of CTG using machine learning methods. However, in the literature, the focus is often only on FHR signals unlike in evaluations performed by obstetricians where the UA signals are also taken into account. In this paper, we propose to model intrapartum CTG recordings from a dynamical system perspective using empirical dynamic modeling with Gaussian processes, which is a Bayesian nonparametric approach for estimation of functions.Results and Discussion: In the context of our paper, Gaussian processes are capable for simultaneous estimation of the dimensionality of attractor manifolds and reconstructing of attractor manifolds from time series data. This capacity of Gaussian processes allows for revealing causal relationships between the studied time series. Experimental results on real CTG recordings show that FHR and UA signals are causally related. More importantly, this causal relationship and estimated attractor manifolds can be exploited for several important applications in computerized analysis of CTG recordings including estimating missing FHR samples, recovering burst errors in FHR tracings and characterizing the interactions between FHR and UA signals.

Objective: To determine the relationship between intrapartum contraction frequency, rest interval duration, and cervical dilation speed and the risk of neonatal hypoxic-ischemic encephalopathy (HIE).Study Design: This was a retrospective case-control study conducted in a maternity hospital in Dublin, Ireland. Babies born without major congenital anomalies between September 2006 and November 2017 at ≥ 35 + 0 weeks' gestational age were eligible. Cases were diagnosed with moderate-severe HIE. The controls were the first eligible baby born before and after each case with normal Apgar scores and not admitted to the neonatal unit. Intrapartum uterine activity was assessed by automated analysis of external tocography recordings. Cervical dilation was assessed by linear interpolation between vaginal examination measurements. The speed of cervical dilation was expressed as the times from 4 to 6 cm, >6 cm to the start of pushing, and from pushing to delivery.Results: Intrapartum tocographs results were available in 49 of 88 cases and 121 of 176 controls. The median contraction rate in cases was 7.7 (Interquartile range [IQR]: 6.6-9.0) compared to 7.0 in controls (IQR: 6.2-7.9) (p = 0.021). The median rest interval duration was 56 s (IQR: 38-76) in cases and 62 s (IQR: 50-79) in controls (p = 0.058). Cases took longer to progress from > 6 cm to the start of pushing (cases: 02:58 [01:14-04:49], controls: 01:48 [00:51-03:34], p = 0.020) and from pushing to delivery (cases: 00:34 [00:24-01:10], controls: 00:27 [00:13-00:56], p = 0.036).Conclusions: Higher contraction frequencies and slower progress towards the end of labour are both independently associated with the risk of moderate-severe HIE. Inter-contraction rest interval duration as measured by external tocography does not provide additional accuracy. [ABSTRACT FROM AUTHOR]

In-vitro fertilization (IVF) is the most advanced treatment for infertility problems; however, its failure rate is still above 70% and the exact causes are often unknown. There is increasing evidence of the involvement of uterine contractions in IVF failure, especially during and after embryo transfer (ET). In this paper, we propose a new method to predict the success of IVF based on quantitative features extracted from electrohysterography (EHG) and B-mode transvaginal ultrasound (TVUS) recordings. To this end, probabilistic classification of the uterine activity, as either favorable or adverse to embryo implantation, is investigated using machine learning. Prior to machine learning, an additional method for EHG and TVUS feature extraction is here proposed that is based on singular value decomposition of the acquired EHG and TVUS recordings. Sixteen women were measured during three phases of the IVF treatment: follicular stimulation (FS), one hour before embryo transfer (ET1), and five to seven days after ET (ET5-7). After feature space reduction by correlation filtering, three machine-learning models, namely, support vector machine (SVM), K-nearest neighbors (KNN), and Gaussian mixture model (GMM), were optimized and tested by nested leave-one-out cross validation for their ability to predict successful embryo implantation. The highest accuracy (93.8%) was achieved by KNN in all phases and by SVM and in the FS and ET1 phases. Contraction frequency, unnormalized first moment and standard deviation, obtained from EHG and TVUS analysis, were the best features selected by the three classifiers. Our results show a multi-modal, multi-parametric strategy based on quantitative features to represent a novel, promising option for prediction of successful embryo implantation, overcoming the limitations of alternative approaches based on qualitative assessment of clinical variables. Yet, a larger dataset is required for improved training of the classifiers, as well as to assess their clinical value in the context of IVF procedures.

• Recommendations on optimal contraction frequency are poorly substantiated by literature. • No distinction in recommendations is made based on presence/absence of FHR abnormalities. • In case of FHR abnormalities, >4 contractions are associated with fetal hypoxia. • We suggest to aim for a maximum contractions frequency of 4 in these women. Current guidelines provide little supporting literature for the definition of uterine tachysystole during labour and no distinction is made for optimal contraction frequency depending on the clinical situation. We hypothesize that fetal hypoxia is frequently caused by uterine tachysystole and that high uterine contraction frequencies are especially harmful when fetal heart rate (FHR) abnormalities are present. We studied the association between contraction frequency and fetal scalp pH values in women with an indication for fetal blood sampling (FBS) based on FHR abnormalities. A retrospective study including 762 women was performed in a tertiary teaching hospital in the Netherlands from January 2015 until January 2020. Women with a singleton pregnancy with a gestational age ≥ 34+0 weeks were included when FBS was performed because of suspicious or pathological FHR tracings. Exclusion criteria were maternal age < 18 years, failed fetal scalp pH values, lack of thirty minute registration by tocodynamometry prior to FBS, poor quality of uterine monitoring, intrauterine resuscitation in the thirty minutes prior to FBS, maternal body mass index ≥ 30 kg/m2 and neonatal birth weight < 10th percentile. Uterine contractions in the thirty minutes prior to FBS were manually annotated by a researcher who was blinded to FBS values, FHR and other obstetrical data. Linear and logistic analysis were used to explore the association between uterine contraction frequency and FBS results. Low fetal scalp pH values were significantly associated with contraction frequency prior to FBS. Fetuses of women with four to five contractions per ten minutes prior to FBS were 2.4 times more likely to have hypoxia as compared to fetuses of women with two to three contractions per ten minutes (aOR 2.4, 95% CI 1.1–5.4). With increasing contraction frequency, the risk of fetal hypoxia further increased. Contraction frequency above four per ten minutes prior to FBS is significantly associated with fetal hypoxia in women with FHR abnormalities. We suggest to aim for a maximum contraction frequency of four per ten minutes in these women. [ABSTRACT FROM AUTHOR]

Abstract Background Increased uterine activity (UA) may not allow adequate recovery time for foetal oxygenation. Methods The aim of the study was to determine if increased UA during labour is associated with an increased risk of either short- or long-term neurological injury in term neonates, or with neonatal proxy measures of intrapartum hypoxia-ischemia. MEDLINE, CINAHL, and ClinicalTrials.gov were searched using the following terms: uterine activity, excessive uterine activity, XSUA, uterine hyperstimulation, and tachysystole. Any study that analysed the relationship between UA during term labour and neurological outcomes/selected proxy neurological outcomes was eligible for inclusion. Outcomes from individual studies were reported in tables and presented descriptively with odds ratios (OR) and 95% confidence intervals (CI) for dichotomous outcomes and means with standard deviations for continuous outcomes. Where group numbers were provided, ORs and their CIs were calculated according to Altman. Main results Twelve studies met the inclusion criteria. Seven studies featured umbilical artery pH as an individual outcome. Umbilical artery base excess and Apgar scores were both reported as individual outcomes in four studies. No study examined long term neurodevelopmental outcomes and only one study reported on encephalopathy as an outcome. The evidence for a relationship between UA and adverse infant outcomes was inconsistent. The reported estimated effect size varied from non-existent to clinically significant. Conclusions There is some evidence that increased UA may be a non-specific predictor of depressed neurological function in the newborn, but it is inconsistent and insufficient to support the conclusion that an association generally exists.

Monitoring the progression of uterine activity provides important prognostic information during pregnancy and delivery. Currently, uterine activity monitoring relies on direct or indirect mechanical measurements of intrauterine pressure (IUP), which are unsuitable for continuous long-term observation. The electrohysterogram (EHG) provides a non-invasive alternative to the existing methods and is suitable for long-term ambulatory use. Several published state-of-the-art methods for EHG-based IUP estimation are here discussed, analyzed, optimized, and compared. By means of parameter space exploration, key parameters of the methods are evaluated for their relevance and optimal values. We have optimized all methods towards higher IUP estimation accuracy and lower computational complexity. Their accuracy was compared with the gold standard accuracy of internally measured IUP. Their computational complexity was compared based on the required number of multiplications per second (MPS). Significant reductions in computational complexity have been obtained for all published algorithms, while improving IUP estimation accuracy. A correlation coefficient of 0.72 can be obtained using fewer than 120 MPS. We conclude that long-term ambulatory monitoring of uterine activity is possible using EHG-based methods. Furthermore, the choice of a base method for IUP estimation is less important than the correct selection of electrode positions, filter parameters, and postprocessing methods. The presented review of state-of-the-art methods and applied optimizations show that long-term ambulatory IUP monitoring is feasible using EHG measurements.

Research objective: to study the use of uterine activity and variables of acceleration capacity (AC) and deceleration capacity (DC) in uterine contractile activity and fetal well-being monitoring in women at risk of preterm birth. Materials and methods. 292 pregnant women were included in the prospective study. All involved women underwent ultrasound cervicometry at 16 weeks. 124 pregnant women with a “short cervix” of the III (main) group were observed in the dynamics, as well as uterine activity and fetal AC/DC at 26, 32 and 38 weeks of gestation, and during labor were studied. In 112 women of group II the variables of fetal AC/DC were detected at these terms of pregnancy. They were monitored via conventional cardiotocography during labor. 56 pregnant women in group I with normal cervicometry were monitored. Results. Sensitivity and specificity of the diagnosis of the threatened preterm birth in the main group was 97.30% and 94.74% respectively. Diagnostic accuracy in the case of uterine activity according to fetal non-invasive electrocardiography was 96.18%. Sensitivity and specificity of the diagnosis of the threatened preterm birth in the comparison group were significantly lower: 89.29% and 87.80% respectively. The diagnostic accuracy was 88.41%. Patients in all clinical groups at 26 weeks had low AC/DC values. However, later in women of group I was found highest AC/DC level. AC/DC values in patients with risk of preterm birth were reduced compared with controls (p < 0.05). Sensitivity and specificity of the diagnosis of fetal distress if AC/DC was used were 91.67% and 99.12% respectively. Diagnostic accuracy of the test was 98.41%. In the comparison group the sensitivity was 77.78%, and the specificity was 89.22%. Diagnostic accuracy of intranatal cardiotocography was 86.82%. Conclusions. Uterine activity extracted from the maternal abdominal signal can significantly improve the diagnosis of the threatenedpreterm delivery. Patients at risk of preterm birth have a delayed fetal neurological, which leads to fetal distress. AC/DC variables obtained via fetal non-invasive electrocardiography allow increasing the accuracy of fetal distress diagnosis.

The relatively limited understanding of the physiology of uterine activation prevents us from achieving optimal clinical outcomes for managing serious pregnancy disorders such as preterm birth or uterine dystocia. There is increasing awareness that multi-scale computational modeling of the uterus is a promising approach for providing a qualitative and quantitative description of uterine physiology. The overarching objective of such approach is to coalesce previously fragmentary information into a predictive and testable model of uterine activity that, in turn, informs the development of new diagnostic and therapeutic approaches to these pressing clinical problems. This article assesses current progress towards this goal. We summarize the electrophysiological basis of uterine activation as presently understood and review recent research approaches to uterine modeling at different scales from single cell to tissue, whole organ and organism with particular focus on transformative data in the last decade. We describe the positives and limitations of these approaches, thereby identifying key gaps in our knowledge on which to focus, in parallel, future computational and biological research efforts. [ABSTRACT FROM AUTHOR]

Objective: Electrohysterography is a non-invasive technique to monitor uterine activity and has a significantly higher sensitivity compared to conventional external tocodynamometry. Whether this technique could lead to improved obstetrical outcomes is still unknown. In this propensity score matched study, clinical results of the first pilot implementing electrohysterography during labor were evaluated. The hypothesis tested is that electrohysterography will help to optimize uterine activity and thereby lead to fewer obstetric interventions. Secondary outcomes were Apgar score, arterial umbilical pH values, first stage labor duration, episiotomy rate and postpartum vaginal blood loss.Study Design: From November 2017 until October 2018, electrohysterography was introduced as a standard alternative for monitoring uterine activity in high-risk deliveries. It could be applied in case of induced labor, previous cesarean delivery, body mass index ≥30 kg/m2 or an inadequate external tocodynamometry monitoring. Outcomes were compared to a matched group of women in which external tocodynamometry was applied for uterine activity monitoring during labor. These women were identified using propensity scores.Results: A total of 348 women received electrohysterography as standard method of uterine monitoring during labor. A match (1:1 ratio) was found for 317 women, resulting in a total population of 634 women. No significant differences were seen in obstetric interventions (i.e. cesarean deliveries and assisted vaginal deliveries) between the electrohysterography and tocodynamometry group (P = 0.80). No statistically significant differences were seen regarding the secondary outcomes.Conclusions: This first pilot study implementing electrohysterography as monitoring method during labor in a high-risk population did not result in statistically significant differences regarding obstetric interventions, low Apgar scores or low umbilical artery pH values. Therefore, we suggest that electrohysterography causes no harm and we recommend further implementation and evaluation in clinical practice. [ABSTRACT FROM AUTHOR]

Objectives: To investigate if tachysystole was associated with an increased risk of cesarean section or unfavorable maternal or neonatal outcomes following induction of labor by misoprostol vaginal inserts.Study Design: We conducted a retrospective cohort study of 446 women over 37 weeks of gestation admitted for labor induction by misoprostol vaginal inserts between May 2016 and May 2017. Fetal heart rate and uterine activity tracings were assessed for tachysystole, defined as ≥ 6 contractions per 10 min, averaged over a 30-minute window. Univariate analysis was performed by using t-test and Chi-square, comparing demographics, pregnancy characteristics, intrapartum monitoring, mode of delivery, neonatal outcomes (Apgar score < 7 at 5 min, umbilical cord artery pH < 7.10, neonatal intensive care unit admission) and maternal outcomes, with regard to the presence of tachysystole. The association between tachysystole and cesarean section was evaluated after adjusting for potential confounders by a modified Poisson regression model, expressed as an adjusted risk ratio and 95 % confidence intervals.Results: A total of 140 women (31.4 %) presented with tachysystole. The median duration of tachysystole was 2 h 12 min. The rate of cesarean section was 25.0 % (N = 35) among patients with tachysystole and 19.6 % (N = 60) for those without tachysystole. Presence of tachysystole during induction of labor with misoprostol vaginal inserts was not associated with cesarean section (adjusted risk ratio,1.0; 95 % confidence interval, 0.7-1.4). Neonatal and maternal outcomes were similar between mothers who did and did not experience tachysystole.Conclusions: This study illustrates that tachysystole is not associated with an increased risk of cesarean section after induction of labor by misoprostol vaginal inserts. The impact of excessive uterine activity on the fetal wellbeing defined by the frequency of uterine contraction alone is probably insufficient. Further research on the development of accurate measures of uterine contractility is necessary to better understand its effect on fetal well-being. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the tocolytic properties of Ananas comosus extract in rat and human uterine tissue in vitro and in the rat in vivo. Organ bath technique was employed to perform functional studies in vitro. The PhysioTel transmitter was implanted in SD rats to measure the changes in intrauterine pressure (IUP) in vivo. Analyses of F2 was performed using LC-HRMS. F2 produced a non-selective inhibitory response on oxytocin, prostaglandin F2α, acetylcholine and KCl. The inhibitory activity of F2 on oxytocin-induced contraction was not attenuated by propranolol, TEA, glibenclamide and indomethacin. Nω-Nitro-L-arginine, a nitric oxide synthase inhibitor, suppressed the maximal tocolytic activity of F2 by 25%. DIDS, an inhibitor of chloride channels, appeared to suppress the relaxant effect of F2. F2 suppressed the oxytocin-induced contraction in Ca 2+ free solution. The in vivo tocolytic activity of F2 and ritodrine were observed in non-pregnant rats during the estrous stage by suppressing the frequency and amplitude of IUP peaks following intrauterine administration. Chemical analysis confirmed the involvement of citric acid in the tocolytic activity of F2. However, another less polar fraction is essential to accompany citric acid to produce such potent inhibitory response of F2. It is likely that F2 exerted tocolytic activity by multiple mechanisms, including antagonizing L-type Ca 2+ channels, interfering with the intracellular Ca 2+ release mechanism and releasing nitric oxide. F2 would be a promising candidate to develop as a tocolytic agent. [ABSTRACT FROM AUTHOR]

The assessment of uterine contractions is important in clinical decision-making, but the precise role for appraising contractions remains controversial. Four clinical approaches to assessing contractions are available: manual palpation; intrauterine pressure determination; external tocodynamometry; and electrohysterography. Palpation is inexpensive and harmless but requires the constant bedside presence of a trained observer. Intrauterine pressure measurement is considered the most sensitive and specific technique, and has become the standard by which other methods are judged; however, its quantitative measurements are not always precise or reproducible. Moreover, the availability of intrauterine pressure measurements does not seem to improve maternal or neonatal outcomes in most situations. External tocodynamometry is the most widely used technique. It is easy to apply and provides reasonably accurate information about the frequency and duration of contractions, but not their amplitude. It can require frequent adjustment during labor and might not work well in patients who are obese. Electrohysterography is a recently available noninvasive technology that detects uterine electrical activity using electrodes placed on the mother's abdominal wall. This approach is at least as reliable and accurate as tocodynamometry. [ABSTRACT FROM AUTHOR]

It is known that the cervical length is a predictive factor for pregnancy evolution to term, but there have not been conducted any trials yet to correlate it with myometrial electrical activity on long term. Nowadays, we don't dispose of a simple, widely available technique to objectively monitor uterine contractility during pregnancy, in order to assess the risk of preterm birth. Our aim was to evaluate the relation between clinical elements, the cervical length and the uterine contractility as recorded by antepartum electromyography. In this study were included 113 women with singleton pregnancies, with gestational age 20-29 weeks divided in two groups: 44 women with short cervical length and 69 with cervical length >25mm. The cervical length is indirectly correlated to the mean contraction frequency, and the contraction percentage was significantly lower in the normal cervix group when compared to the short cervix group. The mean number of contractions was slight increase in the short cervix group (11.27±9.59 vs 9.80±7.05 contractions/hour). 58% of the short cervix patients present a significantly high number of contractions/hour, of low amplitude, and more than 55% present great amplitude and duration of contractions. About 67% of the short cervix patients present high contraction areas. Maternal activity between 10 am-11pm was more pronounced for both study groups. Electromiography has proven its efficacy and utility in obstetrical practice for identify a short cervix, which is a risk factor for premature birth, and recommend the proper treatment. [ABSTRACT FROM AUTHOR]

A need assessment exercise at various resource-limited hospitals in Ghana revealed that a conventional method of monitoring uterine contractions is employed. This method is time consuming and ineffective with a likelihood of misrepresenting data on uterine contractions. There is therefore a need for a system that can potentially overcome the identified challenges. In this paper, the authors present the proof of concept for development of an automated uterine contraction monitoring system designed for use in resource-limited settings. Following the engineering design process, data were gathered to draft product specifications. Various concepts were evaluated and a mathematical model of chosen concept was built and simulated. A functional prototype was constructed to test the system's ability to measure the frequency and average duration of muscle contractions over a specified interval. The results indicate the capability of the chosen concept to meet design specifications. The design can also be enhanced to provide the intensity of contractions. [ABSTRACT FROM AUTHOR]

It is widely accepted that uterine contractions are generated by the electrical activity of myometrial cells. Early in gestation, this electrical activity is low and becomes more intense and synchronized later in pregnancy, peaking at term. Actual technology allows recording and characterizing electromyographic signals, using electrodes placed on the abdominal surface. This is a noninvasive technique, electrohysterograpy (EMG), which can be used to monitor human uterine electrical events. In clinical settings, it could help the clinician to differentiate uterine contractions that will lead to delivery, premature or at term, from physiological uterine activity. As the key of preterm labor is prevention and treatment, EMG could be an important tool to use for this purpose. We are describing the available techniques and their applications. [ABSTRACT FROM AUTHOR]

Introduction: Because little is known about the effects of maternal position on periodic changes in the maternal heart rate (MHR) in late pregnancy, a prospective observational study was done at Tygerberg Academic Hospital in Cape Town. Pregnant women admitted for elective cesarean section were studied to determine the effect of changes in position on the maternal and fetal heart rates (FHR) and maternal blood pressure.Material and Methods: Continuous transabdominal non-invasive recording of MHR, FHR patterns and uterine activity was done for 1 h in 119 women, using the AN24 device from Monica Health Care. Maternal position was changed every 15 min from lateral to supine, then to the other lateral position and finally supine again. Blood pressure was measured in the left arm and left lower leg three times during each 15-min period.Results: MHRs were four beats per minute slower in the left lateral position than in the right lateral position. Periodic MHR changes were seen in 13 (10.9%) women. Most of these (84.6%) were associated with uterine activity and not with maternal position. No changes in FHR patterns were observed after position changes.Conclusions: In a subgroup of pregnant women at term, uterine activity was associated with periodic decelerations of the MHR. In low risk pregnancies there seems to be no effect on the FHR pattern. Implications for the compromised fetus have not yet been investigated. [ABSTRACT FROM AUTHOR]

Key content: Oxytocin is a well‐established drug with a long history of use.The generation of intrauterine pressure is a result of myometrial activity, but is attenuated by a softening cervix.The introduction of active management regimens have not changed the outcome of labour as we envisaged.Too many babies suffer asphyxia as a result of misuse of oxytocin.Some form of education programme must be developed to warn of the dangers of this very useful drug.Better training and education programmes must be in place for midwives and obstetricians for labour management and cardiotography interpretation. Learning objectives: To outline the history of the development of oxytocin.To understand the mechanism of intrauterine pressure development.To understand the methods of intrauterine pressure measurement and assessment.To understand the development of principles of active management with a discussion of the subsequent studies analysing the results of such labour management.To outline the medicolegal aspects of labour augmentation, with particular reference to oxytocin use.To discuss possible implications for the future. Ethical issues: Should all women be given the information that oxytocin augmentation of slow labour may reduce the duration of labour by several hours but does not change the mode of delivery, whilst carrying a risk of causing fetal asphyxia?Should women sign informed consent before their labours are augmented?Should augmentation of labour only be undertaken under the direct supervision of a senior clinician? [ABSTRACT FROM AUTHOR]

Objective: Limited data exist regarding uterine contraction intensity prior to membrane rupture. Using a novel technique of electrical uterine myography (EUM) we aimed to determine which factors affect myometrial activity during active phase of labor. Methods: EUM was prospectively measured in 37 women with singleton pregnancy at term during the active phase of labor until membranes’ rupture. EUM was measured using non-invasive nine channels recorder with an EMG amplifier and three-dimensional position sensor. Uterine electrical activity was quantified with the EUM-index, defined as the mean electrical activity of the uterine muscle over a period of 10 min and measured in units of micro-Joule (microwatt per second [mW/s]). Results: The mean EUM-index at the first 10 min of the measurement was 3.3 ± 0.6 mW/s. In a stepwise linear regression model accounting potential confounders EUM was significantly affected by cervical dilatation (p = 0.005), maternal age (p = 0.04) and previous cesarean delivery status (p = 0.02). In a repeated measurement assessment of non-parametric Fridman’s test for all subjects who had at least 10 continuouss EUM measurements, there was a significant increase in electrical uterine activity as labor progressed (p = 0.01). Conclusion: Electrical uterine activity during the active phase of labor prior to rupture of membranes is affected by maternal age, previous cesarean delivery status and cervical dilatation. Moreover, electrical uterine activity is enhanced throughout labor. [ABSTRACT FROM PUBLISHER]

Objective: To estimate the association between contraction patterns in labor and neonatal outcomes. Methods: A nested case-control study within a consecutive term birth cohort included women in labor with intrauterine pressure catheters (IUPCs) who reached the second stage. Cases were women delivering neonates with composite morbidity: special care or intensive care unit admission, umbilical artery pH ≤ 7.1 or 5-min Apgar < 7. The control group delivered without any components of the composite morbidity. Contraction frequency, duration, relaxation time, Montevideo units (MVUs) and baseline tone in the last 30 min prior to delivery were compared. We used logistic regression to adjust for potential confounders and receiver operating characteristic curves to evaluate the ability of contraction parameters to predict adverse neonatal outcomes. Results: There were 183 cases of adverse neonatal outcomes and 2172 controls without the composite outcome. Contraction duration, relaxation time, MVUs and baseline tone did not significantly differ between the groups. Tachysystole was more common in women with the adverse neonatal outcome (21% versus 15%, p = 0.01). A model including tachysystole, oxytocin use and nulliparity did not adequately predict the adverse outcome (AUC = 0.61). Conclusions: Although tachysystole is associated with adverse neonatal outcomes, uterine activity cannot be used to predict neonatal outcome. [ABSTRACT FROM AUTHOR]