Search

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.

Introduction: Preterm birth (PTB) is common, occurring in over 10% of all live births globally, and is increasing worldwide. The limitations of traditional biomarkers of PTB, such as fetal fibronectin (fFN) and phosphorylated insulin-like growth factor-binding protein-1 (phIGFBP-1) have been well demonstrated in the literature. Therefore, augmenting clinical assessment with newer biomarkers, such as placental alpha macroglobulin-1 (PAMG-1); PartoSure, has the potential to improve disease monitoring and the best interventions. Areas covered: The present expert opinion evaluates the utility and limitations of PAMG-1; PartoSure as a biomarker for PTB in light of the current literature. Expert opinion: Although fFN, phIGFBP-1 and PAMG-1; PartoSure test had similar negative predictive value (NPV) and negative likelihood ratio (LR-), the PAMG-1; PartoSure test had the highest specificity, positive predictive value (PPV), and positive likelihood ratio (LR+) across all at-risk pregnant women. Although findings of this review may be encouraging, the PartoSure test should not be interpreted as absolute evidence for prediction of PTB. The PartoSure test result should always be used in conjunction with information available from the clinical evaluation of the pregnant woman and other diagnostic procedures such as cervical examination, assessment of uterine activity, and evaluation of other risk factors.

Introduction Labor dystocia is the most common cause of cesarean birth in the United States, yet how dystocia develops during labor remains elusive. Uterine activity monitoring has significant potential for advancing our understanding of labor dystocia. While evaluating contraction frequency and amplitude is a common component of labor dystocia management, the literature describing the relationship between measures of uterine activity and labor dystocia is heterogeneous and has not been synthesized to identify the best methods for use in clinical investigation. Methods We conducted a literature search for original research exploring the relationship between uterine activity and labor dystocia published between 2000 and 2019. Included articles were critically reviewed and synthesized. Results Across 11 identified studies, investigators employed 3 different techniques for monitoring uterine activity and 9 different measures were employed. Uterine activity measures, including Montevideo units, uterine electromyography power density spectrum and sample entropy, and the fall-to-rise ratio of contraction shape, detected patterns associated with labor dystocia or cesarean birth. Discussion The use of multiple regression with clinical covariates and a uterine activity measure increased the accuracy of predicting cesarean delivery. Uterine electromyography may be especially useful to evaluate labor dystocia phenotypes to differentiate uterine muscle fatigue from understimulation and lead to algorithms for increased precision in the diagnosis of labor dystocia and innovative approaches to treatment.

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.

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.

Fetal electrocardiography is a valuable alternative to standard fetal monitoring. Suppression of the maternal electrocardiogram (ECG) in the abdominal measurements, results in fetal ECG signals, from which the fetal heart rate (HR) can be determined. This HR detection typically requires fetal R-peak detection, which is challenging, especially during low signal-to-noise ratio periods, caused for example by uterine activity. In this paper, we propose the combination of a convolutional neural network and a long short-term memory network that directly predicts the fetal HR from multichannel fetal ECG. The network is trained on a dataset, recorded during labor, while the performance of the method is evaluated both on a test dataset and on set-A of the 2013 Physionet /Computing in Cardiology Challenge. The algorithm achieved a positive percent agreement of 92.1% and 98.1% for the two datasets respectively, outperforming a top-performing state-of-the-art signal processing algorithm.

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.

During labour, the uterus itself is vulnerable to hypoxia/ischemia that can occur with each strong contraction and this may ultimately cause dysfunctional labour in some women. Periods of Intermittent re-oxygenations are beneficial to tissues subjected to hypoxia to wash out metabolic by-products that have been accumulated during hypoxic stresses which may affect the tissue viability. We proposed that short intermittent hypoxic episodes may protect the uterus from subsequent sustained long hypoxia. To investigate this, two sets of experiments were performed on term-pregnant and nonpregnant rat uterine tissues. In one set of experiment the uterus was subjected to sustained long hypoxia for 40 min and then allowed to recover in 100% O2. In the other set of experiment the uterus was subjected to 3 cycles of 2 min hypoxia each separated by 20 min reoxygenation and followed by a sustained long hypoxia for 40 min and then allowed to recover. We found that challenging the uterine tissues with intermittent short hypoxic episodes improved the uterine contractility significantly after the sustained long hypoxia in term-pregnant but not in non-pregnant tissues. These results suggest that a mechanism of uterine tolerance (preconditioning) is confined to uterine tissues very close to labour and it is a protective phenomenon to improve the uterine activity despite the long-lasting paradoxical metabolic challenges that occur during the repeated strong labour contractions.

Uterine activity plays a crucial role in labor, especially when utero-tonic materials are administered. We aimed to determine the electrical responsiveness of the uterine musculature to labor augmentation with oxytocin using electrical uterine myography (EUM) technology, and to assess whether the kinetics of the EUM device may serve as a predictor for successful vaginal delivery. EUM prospectively measured electrical uterine activity in women with singleton gestations at term (≥ 37 + 0 weeks) undergoing labor augmentation by oxytocin administration. The results were reported as the EUM index, which represented the mean electrical activity in 10-min intervals and measured in units of microwatt per second (mW/s). Measurements were performed at least 30 min before oxytocin initiation and until at least four contractions per 10 min were recorded by standard tocodynamometry. The delta EUM index was defined as the difference between the mean EUM index before and after the initiation of oxytocin. The mean EUM index increased significantly during oxytocin augmentation in all the parturients (P

In this issue, Hautakangas et al report that "we found significantly lower intrauterine pressure (IUP) in failed Trial Of Labour After Caesarean (TOLAC), compared with Vaginal Birth After Caesarean", although "the dosages of oxytocin tended to be higher among failed TOLACs". They commented that "it seems that raising the oxytocin dosage does not necessarily improve uterine contractile activity in this group". Why is this?

What you need to know Preterm birth and its complications account for nearly one million neonatal deaths each year globally.1 Women who present with a dilated cervix in the second trimester are at increased risk of pregnancy loss and preterm birth (fig 1). They generally have no or minimal preceding symptoms such as change in discharge or mild abdominal pain and are detected to have a dilated cervix on examination. Cervical dilatation may also be detected in the anomaly scan. Fig 1 Premature cervical dilatation and exposed unruptured fetal membranes International guidelines from the US, UK, and Canada suggest considering emergency cervical cerclage, or rescue cerclage, to prevent preterm birth in women presenting with cervical dilatation and exposed fetal membranes between 16 and 28 weeks of gestation if there are no signs of bleeding, infection, or uterine activity (see box 1).2 Box 1 ### NICE guidelines for management of preterm labour and birth (NG25)2 #### Women with a closed cervixRETURN TO TEXT

Objective To describe the outcomes of patients transferred to King Edward Memorial Hospital (KEMH) with signs of labour at preterm gestations. Design A retrospective observational study of the 69 cases transferred to KEMH during 2015. Setting Patient transfers from all locations across Western Australia (WA) to the sole tertiary perinatal centre in Perth. Participants Pregnant women within WA with threatened or actual preterm labour (PTL) or preterm prelabour rupture of membranes (PPROM) between 23 and 32 weeks gestation. Main outcome measures The occurrence of delivery during the admission and time-to-delivery as well as length of admission and association between clinical factors and time-to-delivery. Results The percentage of the study population delivered during the admission following transfer was 72.5%. Eighty-six per cent of those who delivered did so within 72 hours of transfer. The median time from transfer to delivery was 1 day. Sixty-three per cent of those who did not deliver during the admission progressed to 36 weeks gestation. Patients transferred with PPROM were less likely to deliver during the admission compared to those with uterine activity (50% versus 19.6%, P = 0.007) and nulliparas were more likely to deliver (93.5% versus 55.3%, P Conclusion The majority of women transferred with signs of PTL progress to delivery during the same admission with the highest risk of delivery being the first 72 hours following transfer. If the pregnancy is ongoing at 72 hours, there is a reasonable chance of progression to late preterm gestation supporting the return of woman to their place of origin for antenatal care following discharge.

Antenatal corticosteroids before preterm births are considered to be most effective 48 h after and up to 1 week after the first dose. We aim to evaluate: (1) our practice of administration of antenatal corticosteroids in Singapore; (2) admission characteristics of women for discriminatory factors of spontaneous preterm delivery within 1 week. This is a retrospective study in a tertiary obstetrics unit in Singapore. 3044 women who delivered live births (at term or preterm) from 1st November 2014 to 31st January 2015, who were at risk of spontaneous or induced preterm delivery, were included. Data related to the time of and indications for antenatal corticosteroids administration, characteristics assessed at the time of presentation, and time of delivery were collected and analysed. 85.9% of women who delivered at gestational age ≤ 34+6 received at least one dose. 22.1% had delivered within the window of efficacy. Gestational age > 32 weeks at presentation, uterine activity on tocography and cervical dilation with effacement were associated with preterm delivery within 1 week of presentation. Overall, our antenatal corticosteroids administration rate is comparable to that attained by centres in other developed countries. It is difficult but important to discriminate women who will benefit from this timely intervention.

Objective: Electronic fetal monitoring (EFM) correlates poorly with neonatal outcome. We present a new metric: the “Fetal Reserve Index” (FRI), formally incorporating EFM with maternal, obstetrical, fetal risk factors, and excessive uterine activity for assessment of risk for cerebral palsy (CP). Methods: We performed a retrospective, case-control series of 50 term CP cases with apparent intrapartum neurological injury and 200 controls. All were deemed neurologically normal on admission. We compared the FRI against ACOG Category (I-III) system and long-term outcome parameters against ACOG monograph (NEACP) requirements for labor-induced fetal neurological injury. Results: Abnormal FRI's identified 100% of CP cases and did so hours before injury. ACOG Category III identified only 44% and much later. Retrospective ACOG monograph criteria were found in at most 30% of intrapartum-acquired CP patients; only 27% had umbilical or neonatal pH Conclusions: In this initial, retrospective trial, an abnormal FRI identified all cases of labor-related neurological injury more reliably and earlier than Category III, which may allow fetal therapy by intrauterine resuscitation. The combination of traditional EFM with maternal, obstetrical, and fetal risk factors creating the FRI performed much better as a screening test than EFM alone. Our quantified screening system needs further evaluation in prospective trials.

The rate of labor induction is steadily increasing and, in industrialized countries, approximately one out of four pregnant women has their labor induced. Induction of labor should be considered when the benefits of prompt vaginal delivery outweigh the maternal and/or fetal risks of waiting for the spontaneous onset of labor. However, this procedure is not free of risks, which include an increase in operative vaginal or caesarean delivery and excessive uterine activity with risk of fetal heart rate abnormalities. A search for “Induction of Labor” retrieves more than 18,000 citations from 1844 to the present day. The aim of this review is to summarize the controversies concerning the indications, the methods, and the tools for evaluating the success of the procedure, with an emphasis on the scientific evidence behind each.

Fetal well-being is commonly assessed by monitoring the fetal heart rate (fHR). In clinical practice, the de facto standard technology for fHR monitoring is based on the Doppler ultrasound (US). Continuous monitoring of the fHR before and during labor is performed using a US transducer fixed on the maternal abdomen. The continuous fHR monitoring, together with simultaneous monitoring of the uterine activity, is referred to as cardiotocography (CTG). In contrast, for intermittent measurements of the fHR, a handheld Doppler US transducer is typically used. In this article, the technology of Doppler US for continuous fHR monitoring and intermittent fHR measurements is described, with emphasis on fHR monitoring for CTG. Special attention is dedicated to the measurement environment, which includes the clinical setting in which fHR monitoring is commonly performed. In addition, to understand the signal content of acquired Doppler US signals, the anatomy and physiology of the fetal heart and the surrounding maternal abdomen are described. The challenges encountered in these measurements have led to different technological strategies, which are presented and critically discussed, with a focus on the US transducer geometry, Doppler signal processing, and fHR extraction methods.

[EN] Background: Uterine activity monitoring is an essential part of managing the progress of pregnancy and labor. Although intrauterine pressure (IUP) is the only reliable method of estimating uterine mechanical activity, it is highly invasive. Since there is a direct relationship between the electrical and mechanical activity of uterine cells, surface electrohysterography (EHG) has become a noninvasive monitoring alternative. The Teager energy (TE) operator of the EHG signal has been used for IUP continuous pressure estimation, although its accuracy could be improved. We aimed to develop new optimized IUP estimation models for clinical application. Approach: We first considered enhancing the optimal estimation of IUP clinical features (maximum pressure and tonus) rather than optimizing the signal only (continuous pressure). An adaptive algorithm was also developed to deal with inter-patient variability. For each optimizing signal feature (continuous pressure, maximum pressure and tonus), individual (single patient), global (full database) and adaptive models were built to estimate the recorded IUP signal. The results were evaluated by computing the root mean square errors (RMSe): continuous pressure error (CPe), maximum pressure error (MPe) and tonus error (TOe). Main results: The continuous pressure global model yielded IUP estimates with Cpe = 14.61mm Hg, MPe = 29.17mm Hg and Toe = 7.8mm Hg. The adaptive models significantly reduced errors to CPe = 11.88, MPe = 16.02 and Toe = 5.61mm Hg. The EHG-based IUP estimates outperformed those from traditional tocographic recordings, which had significantly higher errors (CPe = 21.93, MPe = 26.97, and TOe = 13.96). Significance: Our results show that adaptive models yield better IUP estimates than the traditional approaches and provide the best balance of the different errors computed for a better assessment of the labor progress and maternal and fetal wellbeing., This research project was supported by the Spanish Ministry of Economy and Competitiveness, the European Regional Development Fund (DPI2015-68397-R), and by the projects UPV_ FE-2018-C03 and GV/2018/104.

Recent warnings postulate a possible damaging effect of volatile anesthetics on the fetus. In our archive of fetal surgeries, we found wide variation in dosing of volatile anesthetics during spina bifida surgeries. We hypothesized that there was an association between volatile anesthetic exposure and uterine activity.Sixty anesthesia records from spina bifida operations were assessed. We analyzed the course of the administered volatile anesthetic during surgery and calculated from each patient's anesthesia record the volatile anesthetic exposure expressed in vol%h. We divided the records into two post hoc groups of the 20 lowest exposure (Group L) versus the 20 highest exposure (Group H), and compared them for uterine activity and fetal heart rate.The number of contractions per hour was significantly greater in Group H (mean 1.3, SD ± 1.2) compared with Group L (mean 0.5, SD ± 0.6, P=0.049). There was no difference between the groups for the administration of the tocolytic drug atosiban (P=0.29). The course of the mean arterial pressure did not significantly differ but group H needed significantly more vasoactive medication (P0.05).We found that a lower intra-operative volatile anesthetic exposure than recommended in the MOMS-trial (i.e.2.0 minimum alveolar concentration [MAC]) was not associated with an increase in intra-operative uterine activity. This is an indication that during spina bifida surgery, 2.0 MAC may not be necessary to avoid potentially harmful uterine activity.

Evaluation of synchronization between myoelectric signals can give new insights into the functioning of the complex system of porcine myometrium. We propose a model of uterine contractions according to the hypothesis of action potentials similarity which is possible to detect during propagation in the uterine wall. We introduce similarity measures based on the concept of synchronization as used in matching linear signals such as electromyographic (EMG) time series data. The aim was to present linear measures to assess synchronization between contractions in different topographic regions of the uterus. We use the cross-correlation function (ƒx,y[l], ƒy,z[l]) and the cross-coherence function (Cxy[ƒ], Cyz[ƒ]) to assess synchronization between three data series of a diestral uterine EMG bundles in porcine reproductive tract. Spontaneous uterine activity was recorded using telemetry method directly by three-channel transmitter and three silver bipolar needle electrodes sutured on different topographic regions of the reproductive tract in the sow. The results show the usefulness of the cross-coherence function in that synchronization between uterine horn and corpus uteri for multiple action potentials (bundles) could be observed. The EMG bundles synchronization may be used to investigate the direction and velocity of EMG signals propagation in porcine reproductive tract.

Background Studies which use external tocography to explore the relationship between increased intrapartum uterine activity and foetal outcomes are feasible because the technology is safe and ubiquitous. However, periods of poor signal quality are common. We developed an algorithm which aims to calculate tocograph summary variables based on well-recorded contractions only, ignoring artefact and excluding sections deemed uninterpretable. The aim of this study was to test that algorithm's reliability. Methods Whole recordings from labours at ≥35 weeks of gestation were randomly selected without regard to quality. Contractions and rest intervals were measured by two humans independently, and by the algorithm using two sets of models; one based on a series of pre-defined thresholds, and another trained to imitate one of the human interpreters. The absolute agreement intraclass correlation coefficient (ICC) was calculated using a two-way random effects model. Results The training dataset included data from 106 tocographs. Of the tested algorithms, AdaBoost showed the highest initial cross-validated accuracy and proceeded to optimization. Forty tocographs were included in the validation set. The ICCs for the per tocograph mean contraction rates were; human B to human A: 0.940 (0.890–0.968), human A to initial models: 0.944 (0.898–0.970), human A to trained models 0.962 (0.927–0.980), human B to initial models: 0.930 (0.872–0.962), human B to trained models: 0.948 (0.903–0.972). Conclusions The algorithm described approximates interpretation of external tocography performed by trained humans. The performance of the AdaBoost trained models was marginally superior compared to the initial models.

[EN] Postpartum hemorrhage (PPH) is one of the major causes of maternal mortality and morbidity worldwide, with uterine atony being the most common origin. Currently there are no obstetrical techniques available for monitoring postpartum uterine dynamics, as tocodynamometry is not able to detect weak uterine contractions. In this study, we explored the feasibility of monitoring postpartum uterine activity by non-invasive electrohysterography (EHG), which has been proven to outperform tocodynamometry in detecting uterine contractions during pregnancy. A comparison was made of the temporal, spectral, and non-linear parameters of postpartum EHG characteristics of vaginal deliveries and elective cesareans. In the vaginal delivery group, EHG obtained a significantly higher amplitude and lower kurtosis of the Hilbert envelope, and spectral content was shifted toward higher frequencies than in the cesarean group. In the non-linear parameters, higher values were found for the fractal dimension and lower values for Lempel-Ziv, sample entropy and spectral entropy in vaginal deliveries suggesting that the postpartum EHG signal is extremely non-linear but more regular and predictable than in a cesarean. The results obtained indicate that postpartum EHG recording could be a helpful tool for earlier detection of uterine atony and contribute to better management of prophylactic uterotonic treatment for PPH prevention., This work was supported by the Spanish Ministry of Economy and Competitiveness, the European Regional Development Fund (MCIU/AEI/FEDER, UE RTI2018-094449-A-I00-AR) and the Generalitat Valenciana (GV/2018/104 and AICO/2019/220).

[EN] Objective: The objective of this study is to compare the uterine activity response between women administered dinoprostone (prostaglandin E2) and misoprostol (prostaglandin E1) for induction of labour (IOL) by analysing not only the traditional obstetric data but also the parameters extracted from uterine electrohysterogram (EHG). Methods: Two cohorts were defined: misoprostol (25-mg vaginal tablets; 251 women) and dinoprostone cohort (10 mg vaginal inserts; 249 women). All the mothers were induced by a medical indication of a Bishop Score < ¿ 6. Results: The misoprostol cohort was associated with a shorter time to achieve active labour (p ¿ .017) and vaginal delivery (p ¿ .009) and with a higher percentage of vaginal delivery in less than 24 h in mothers with a very unfavourable cervix score (risk ratio (RR): 1.41, IC95% 1.17¿1.69, p ¿ .002). Successful inductions with misoprostol showed EHG parameter values significantly higher than basal state for amplitude and pseudo Montevideo units (PMU) 60¿ after drug administration, while spectral parameters significantly increased after 150¿. This response was not observed in failed inductions. In the successful dinoprostone group, the duration and number of contractions increased significantly after 120¿, PMU did so after 180¿, and no significant differences were found for spectral parameters, possibly due to the slower pharmacokinetics of this drug. Conclusion: Successful inductions of labour by misoprostol are associated with earlier effective contractions than in labours induced by dinoprostone., This work was partially supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under grant [DPI2015-68397-R] and by the company Bial SA.

Electronic fetal monitoring (EFM) is used widely during labor & delivery, but existing solutions limit patient mobility, are uncomfortable, and do not consistently capture fetal heart rate (FHR) and uterine activity (UA) signals. A wireless EFM system was developed that features wearable US and tocodynamometer devices that conform to the body and do not require cables or belts. Benchtop testing demonstrated that the devices can accurately and consistently measure simulated FHRs and UAs over clinically meaningful ranges and body curvatures. The wearable EFM devices are expected to provide more reliable signal capture independent of maternal movement and repositioning, while also significantly improving patient comfort and mobility.

This study examined the extent to which prolonged farrowing and parity are associated with plasma oxytocin concentrations and follicular development of oestrous sows during subsequent insemination. A total of 30 sows were allocated to two groups based on farrowing duration: (i) SHORT (n = 14): 159 ± 29 min, (ii) LONG (n = 16): 533 ± 190 min. The sows were also divided into two parity classes: (i) YOUNG (n = 14): parity 2.5 ± 0.8, (ii) OLD (n = 16): parity 6.4 ± 2.3. After weaning, the ovaries were examined daily with transrectal ultrasound. On the second day of oestrus, blood samples were collected for oxytocin (OT) assay at -15, -10, -5, 0, +1, +2, +3, +4, +6, +8, +10, +15, +20, +25, +30, +40, +50 and +60 min with a boar contact between 0 and +10 min. Boar presence stimulated an increase in OT concentrations (p < .05). During boar presence, OT in the LONG group was higher than in the SHORT group (p < .01). The sows in the OLD group had a longer farrowing duration than in the YOUNG group (p < .05). OT levels and diameters of follicles were more relevant for parity than was the duration of farrowing. We therefore conclude that the OT levels and follicular development of oestrous sows are associated due to parity but difficult to be predicted from the duration of previous farrowing.

Purpose: Uterine activity plays a key role in reproduction, and altered patterns of uterine contractility have been associated with important physiopathological conditions, such as subfertility, dysmenorrhea, and endometriosis. However, there is currently no method to objectively quantify uterine contractility outside pregnancy without interfering with the spontaneous contraction pattern. Transabdominal electrohysterography has great potential as a clinical tool to characterize noninvasively uterine activity, but results of this technique in nonpregnant women are poorly documented. The purpose of this study is to investigate the feasibility of transabdominal electrohysterography in nonpregnant women. Methods: Longitudinal measurements were performed on 22 healthy women in 4 representative phases of the menstrual cycle. Twelve electrohysterogram-based indicators previously validated in pregnancy have been estimated and compared in the 4 phases of the cycle. Using the Tukey honest significance test, significant differences were defined for P values below.05. Results: Half of the selected electrohysterogram-based indicators showed significant differences between menses and at least 1 of the other 3 phases, that is the luteal phase. Conclusion: Our results suggest transabdominal electrohysterography to be feasible for analysis of uterine activity in nonpregnant women. Due to the lack of a golden standard, this feasibility study is indirectly validated based on physiological observations. However, these promising results motivate further research aiming at evaluating electrohysterography as a method to improve understanding and management of dysfunctions (possibly) related to altered uterine contractility, such as infertility, endometriosis, and dysmenorrhea.

Tocodynamometry is the most common method of labor evaluation but most clinicians would agree it has limited utility before 26 weeks of gestation. The obesity epidemic has further reduced our ability to accurately detect uterine contractions using the tocodynamometer at any gestational age. We sought to design and test a novel contraction monitor that bypasses the maternal abdomen.An optimized version of an intravaginal electrohysterographic ring device was tested in an ovine model. The device and its methodology as well as the tocodynamometer were validated against the current gold standard uterine activity monitor, the intrauterine pressure catheter in six sheep at varying gestational ages.Both the intravaginal ring device and the tocodynamometer correlated well with IUPC, r = 0.69 and 0.73, respectively (p 0.001). The number of contractions detected by each monitor remained similar even after accounting for confounders.These results suggest that uterine activity can be monitored from the vaginal interface in an ovine model and offers an alternative clinical tool for the detection of contractions in situations, in which tocodynamometry would be ineffective or intrauterine monitoring inappropriate.

[EN] Labor induction is a common practice to promote uterine contractions and labor onset. Uterine electrohysterogram (EHG) has proved its suitability for characterizing the uterus electrophysiological condition in women with spontaneous labor. The aim of this study was to characterize and compare uterine myoelectrical activity during the first 4h in response to labor induction drugs, Misoprostol (G1) and Dinoprostone (G2), by analyzing the differences between women who achieved active phase of labor and those who did not (successful and failed inductions). A set of temporal, spectral and complexity parameters were computed from the EHG-bursts. As for successful inductions, statistical significant and sustained increases with respect to basal period were obtained for EHG amplitude, mean frequency, uterine activity index (UAI) and Teager, after 60¿ for the G1 group; duration, amplitude, number of contractions and UAI for the G2 group, after 120¿. Moreover, Teager showed statistical significant and sustained differences between successful and failed inductions (1.43±1.45 µV2.Hz2.105 vs. 0.40±0.26 µV2.Hz2.105 after 240¿) for the G1 group, but not in the G2 group, probably due to the slower pharmacokinetics of this drug. These results revealed that EHG could be useful for successful induction prediction in the early stages of induction, especially when using Misoprostol., This research project was supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (DPI2015-68397-R) and by the company Bial SA.

Uterine contraction is one of the most important indication in the labor progression. Electrohysterogram (EHG) is a promising method for monitoring uterine contraction and discriminating efficient and inefficient contractions. This study aims to analyze the difference of EHG signals between two groups. EHG signals are recorded with abdominal electrodes from 20 pregnant women, including 10 in term labor group and 10 in non-labor group. Typical linear and nonlinear characteristics of EHG signals, including root mean square (RMS), peak frequency (PF), median frequency (MDF), mean frequency (MNF), parameters from wavelet decomposition (W4, W5) and time reversibility (Tr) are extracted. These characteristics are compared between contraction and non-contraction in term labor group and non-labor group. The result shows that RMS, W4 and W5 of contraction are significantly larger than non-contraction both within term labor group and between two groups (all p

Electrohysterogram source imaging, i.e., moving from the electrode/sensor space to the source space using EHG signals, provide an estimate of spatial distributions of uterine activity at millisecond scale. This paper aims to study the ability of different distributed source localization methods to recover uterine electrical activity sources. Performance was quantified using a detection accuracy index. Our result suggests that the variation based method is able to reconstruct extended uterus sources with the overall high accuracy, where the increasing of the electrodes numbers and the decreasing of the fat thickness induce a better accuracy in localization.

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.

Successful pregnancy necessitates that the uterus is maintained in a relaxed, quiescent state for the majority of pregnancy, before being transformed to a contractile and excitable phenotype to facilitate parturition. There is now a substantial body of evidence highlighting key upstream regulators involved in this transformation. Despite our rapidly advancing knowledge of myometrial biology, the exact mechanisms that regulate parturition are not yet understood. Further work is necessary to define the complex interactions that form the key regulatory pathways controlling uterine quiescence, contractility, and the transition between the two states. Furthermore, new evidence continues to emerge implicating novel mechanisms that regulate uterine activity during normal and preterm birth. This review examines current evidence pertaining to key upstream regulators that have been implicated in human parturition over the past decades and surveys recent findings that are yet to be integrated into the paradigm of uterine regulation.

Objective: The purpose of this study was to describe uterine activity within the first two hours after placental delivery among low-risk pregnant women.Materials and methods: Participants were 17 low-risk pregnant women who had a singleton birth at midwifery birth centers in Japan. Contractile waves of uterine activity were measured by using an external tocodynamometer.Results: Spontaneous uterine contraction frequency during the first two hours after the placental delivery decreased over time (F9, 54 = 19.7, p

PURPOSE The aim of this study was to determine the quality of intrapartum uterine activity (UA) monitoring in daily practice during the first and second stages of labour. The total duration of inadequate UA monitoring is quantified in relation to the technique applied, namely, external tocodynamometry (TOCO) or electrohysterography (EHG). MATERIAL AND METHODS 144 UA recordings, collected from 1st September 2008 until 15th October 2009 from deliveries at the Marien-Hospital Witten, Germany, were analysed by obstetricians based at different centres. The included recordings were from singleton and simultaneously with external TOCO and EHG monitored pregnancies. External TOCO and EHG UA recordings were blinded. RESULTS The percentages of "adequate" UA recordings in the first and second stages of labour were much higher for the external EHG than the external TOCO mode (p

PURPOSE: To compare diagnostic accuracy of sonographic cervical length (CL) measurement and uterine electric activity assessed by electromyography (EMG) in second trimester regarding prediction of preterm delivery (PTD). ----- METHODS: Prospective study of 308 low-risk women. Shortened CL was defined as ≤25 mm (≤5th centile), while raised EMG activity was defined as the presence of ≥20 action potentials in 20 min of assessment (≥95th centile). Outcome measures were diagnostic accuracy of both tests alone or in combination for prediction of PTD and early PTD (≤34 weeks). ----- RESULTS: The incidence of PTD was 23/308 (7.4%) while the incidence of early PTD was 9/308 (2.9%). Shortened CL and raised EMG activity were significantly related to PTD [prevalence-weighted likelihood ratio (pw-LR) 1.9, 95% CI 1.0-3.5 vs. 9.5, 95% CI 2.5-35.7], but not to early PTD (pw-LR 0.4, 95% CI 0.2-0.8 vs. 0.6, 95% CI 0.3-1.7). Significant predictive value for early PTD was found only if both tests were combined (pw-LR 4, 95% CI 1.3-14.3). ----- CONCLUSION: Shortened CL and raised EMG activity in second trimester have significant diagnostic accuracy regarding prediction of PTD in a low-risk population. However, in order to be useful as a predictor for early PTD both tests must be positive.

Accurate assessment of uterine activity during labor is essential to promote optimal patient outcomes. This review provides clinicians with information to develop an evidence-based, standardized approach to the evaluation and management of uterine activity during labor including identification and treatment of excessive uterine activity. Common terminology is defined in an effort to enhance clear and direct communication and accurate assessment. The latest evidence regarding normal labor is presented along with physiology related to uterine activity and fetal oxygenation. Suggestions for managing excessive uterine activity are offered as well as a synopsis of risk reduction strategies for clinical practice.

There are no reports indicating the effect of prophylactic transabdominal cerclage (TAC) on the prolongation of multifetal pregnancies. We report the use of TAC in triplets, which evolved over 20 years in one practice. A retrospective cohort study of triplet pregnancies was conducted. Obstetric and neonatal outcomes were compared among women who underwent a prophylactic TAC or transvaginal cerclage and no cerclage. Of the 141 women who delivered triplets, prophylactic TAC was associated with reduced incidence of extreme prematurity and improved incidence of neonatal/postnatal survival. With the exception of mode of conception, prepregnancy weight, and the use of home monitoring uterine activity monitor, procardia and terbutaline, no major differences were found in terms of patient characteristics and pregnancy and delivery management among the three groups. It was concluded that in triplet pregnancies, prophylactic placement of a TAC appears to lower the incidence of delivery before 28 weeks.

Background Labor results in the release of sensitizing substances such as progesterone, prostaglandins, cytokines and cortisol, some of which have been observed to participate in sleep regulation. We hypothesized that these substances could affect sleep regulation and therefore the amount of volatile agent required to provide general anesthesia for cesarean delivery. Methods A total of 50 patients were enrolled, of whom 25 had uterine activity less than 30 Montevideo units (Prelabor group) and 25 had uterine activity greater than 80 Montevideo units (Labor group). Anesthesia was maintained with 50% oxygen in nitrous oxide with sevoflurane. Sevoflurane concentration was adjusted to sustain a constant Bispectral Index (BIS) value of 40–55. Prolactin, progesterone and cortisol levels were evaluated immediately before cesarean delivery. Results End-tidal concentrations of sevoflurane in the Prelabor group were higher than in the Labor group with similar Bispectral Index values. No significant differences were found in prolactin, progesterone and cortisol levels between the two groups. Conclusion Anesthetic requirements for sevoflurane, as measured by Bispectral Index, decrease in laboring versus non-laboring parturients undergoing cesarean delivery. Prolactin, progesterone and cortisol do not appear to be responsible for this observation.

The human birth process is powered by uterine contractions that have observable patterns that depend on the physiology of muscular activity. We explored a previously designed model(1) simulating the uterus to assess global contractile patterns. The model is a cellular automaton that simulates the complexities of uterine activity from a few simple rules of cellular interaction and uterine geometry. Multiple experiments using the cellular automaton involved different uterine shapes, cell numbers, and initial distributions of active and resting cells. Results demonstrate complex contraction patterns similar to those observed in human labor. At least 2 modes of behavior appear in the simulations, one consistent with effective labor and one not. Experiments with cellular automata provide insights into stereotypic and disordered labor patterns that produce patient discomfort without progress in labor. We hypothesize that complex uterine contraction patterns may have other roles in the preparation for labor and birth.

Uterine activity measured by quantifying active contraction area in induced labour showed an initial significant steep increase (incremental phase) followed by a stable phase when the uterine activity was about 1750 k Pas/15 min in nulliparae and multi-parae with poor cervical score; it was 1500 k Pas/15 min in multiparae with good cervical score. Once this was achieved, further increase in oxytocin dosage did not increase uterine activity but instead revealed a tendency to hypertonic uterine contractions. A marked rise in uterine activity was observed in the late first stage of labour (terminal phase) despite no increase in oxytocin in patients with good cervical scores (>6) at induction but not in those with poor cervical scores (

A new fibreoptic pressure transducer was used to measure uterine activity in labour, and the results were compared with those obtained with the catheter-tip bridge strain gauge transducer. Readings were obtained from 8 patients in spontaneous labour, and a total of 565 contractions were analysed. When all contractions were analysed the coefficient of variation ranged from 11.24 to 42.74. In 2 patients with vast difference in pressure readings one of the catheters had slipped into the lower uterine segment, when these 2 cases were not considered the coefficient of variation ranged from 11.24 to 21.18. Even in the others there were transient periods lasting 5 to 15 minutes when the pressure difference was greater than 10 mmHg between the 2 catheters. When they were excluded from analysis, along with the 2 cases where one of the catheters was displaced, the coefficient of variation ranged from 9.30 to 16.05. The fibreoptic pressure transducer appears to be a safe, convenient and fairly accurate means of assessing uterine activity. But one must be aware that a catheter giving low readings compared with the initial period soon after insertion may be due to displacement of the transducer tip to the uterine lower segment.

Transport of women in preterm labour in Western Australia is conducted in small fixed wing aircraft over distances up to 2,000 km (1,200 miles). In recent years β-sympathomimetic inhibition of uterine activity has been employed to reduce the risk of delivery during transfer. This study reports the outcome of routine use of this therapy in which at times classical contraindications have not been observed. During 1983 and 1984, 99 consecutive maternal aerial transfers for preterm labour using β-sympathomimetic drugs by infusion resulted in only 1 case of pulmonary oedema and 2 of maternal hyperglycaemia. There were no deliveries during the flights. The results of this study suggest β-sympathomimetic inhibition of uterine activity for women in preterm labour is safe and efficacious therapy for long distance aeromedical evacuation in small aircraft.

Uterine activity was quantified using a transducer tipped intrauterine catheter in 75 nulliparous women with dysfunctional labour. The active contraction area profiles in these women were below the median levels reported for those who had normal progress of labour from our institution. When uterine activity was augmented with oxytocin, 90.7% progressed in labour and delivered vaginally. Six patients (8%) showed poor progress despite good uterine activity and had to be delivered by caesarean section (CS) for failure to progress and signs of cephalopelvic disproportion. The pre- and post-augmentation uterine activity were similar in those who delivered vaginally or by CS and was not helpful in identifying those who had cephalopelvic disproportion. Of the 75 women who had slow progress of labour, 50 had a contraction frequency of less than 1 in 3 min whilst 25 had a minimum frequency of 1 in 3 min or more. All except one in the latter group delivered vaginally when oxytocin was titrated to achieve a contraction frequency of 1 in 2 to 2 1/2 min which were clinically judged to be adequate based on a duration greater than 40 sec. Oxytocin should be titrated to achieve a target contraction frequency of 1 in 2 to 2 1/2 min lasting greater than 40 sec to achieve good obstetric outcome in those with dysfunctional labour.

Objectives. Validation of electrohysterography (EHG) as a method for uterine activity monitoring during labour by comparing with intra-uterine pressure catheter (IUPC) recordings.Design. Prospective observational study.Setting. Labour ward in a tertiary centre in the Netherlands.Population. Thirty-two women in labour.Methods. Simultaneous recording of uterine activity with EHG and IUPC for at least 30 min.Main outcome measures. Number of uterine contractions detected by both EHG and IUPC (sensitivity). Number of contractions detected by EHG only [positive predictive value (PPV)]. Correlation between contraction amplitude and duration measured by EHG and IUPC.Results. EHG detects uterine contractions accurately: sensitivity = 94.5% (95%CI: 87.5–100), PPV = 88.3% (95%CI: 76.2–100). The correlation of contractions' duration and amplitude between both methods is r = 0.31 (95%CI: 0.23–0.39) and r = 0.45 (95%CI: 0.38–0.52), respectively.Conclusions. EHG detects uterine contractions accurately during labour but ...

Calcium entry blockers have a well documented relaxing effect of smooth muscle, vascular as well as non-vascular. Mainly as a consequence of this action, the drugs have been used for treatment of several non-cardiac disorders where hyperactivity of smooth muscle is considered to have an important role in the pathogenesis. In this short review some of these extracardiac effects of calcium entry blockers are discussed and also their clinical application.

A new isolation procedure for Kalata polypeptides from the tropical plant Oldenlandia affinis DC is described. Fractions were screened by thin-layer chromatography, and Van Urk positive fractions were tested for oxytocic activity in estrogenized rat uteri. By using this procedure, we were able to isolate and characterize three macrocyclic polypeptides with uterine activity. Their amino acid sequence and biological effects have been analyzed, and their NMR spectra were compared with those of the earlier ones. All three peptides showed hemolytic activity on human blood, and were tested for antibiotic effect against E. coli, Staphylococccus aureus, and Hemophilus influenzae.

The effects of mycotoxin zearalenone and their major metabolites alpha- and beta-zearalenol on spontaneous contractions in isolated lamb uterine smooth muscle were examined. The study was carried out on 20 female prepubertal lambs aged between 45 and 50 days. Myometrial strips were set up in two isolated organ baths (10ml) at 37 degrees C and were exposed to increasing concentrations (10(-11)M-10(-6)M) of these mycoestrogens and results were compared with the effect, at the same concentrations, of natural estrogen 17beta-estradiol. Our findings suggest that mycotoxins and 17beta-estradiol, at nanomolar concentrations, rapidly enhance phasic spontaneous smooth muscle contraction. In particular, zearalenone increases the uterine activity similarly to 17beta-estradiol. On the contrary, its metabolite alpha-zearalenol significantly inhibits myometrial contractility.

This review critically evaluates the efficacy of different tocolytics in reducing uterine pressure and contractions in term labor. The available evidence supports the use of beta-adrenergic-receptor agonists such as terbutaline or ritodrine; they appear to have an immediate and comparable profound effect on uterine activity in term labor. However, the preferred type of beta-adrenergic receptor agonist and dosage are unclear. The oxytocin receptor antagonist atosiban has a high specificity for the uterus with limited or no systemic effects and could therefore be an attractive alternative for use in term labor. The evidence on the tocolytic potency of a single bolus of atosiban for tocolysis in term labor is encouraging but limited and needs further research. Moreover, atosiban lacks United States Food and Drug Administration approval. Literature documenting efficacy and safety of nitroglycerin or magnesium sulfate in term labor is far from convincing. The theoretical basis for the use of tocolytics for nonreassuring intrapartum fetal heart rate patterns is to reduce the aggravating influence of uterine contractions. However, the clinical evidence that tocolytics in term active labor are actually beneficial in improving neonatal outcome is very limited. Target Audience: Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader should be able to outline the available literature pertaining to tocolysis for term labor and appraise the effectiveness of various tocolytics in term labor.

With an overall effectiveness below 30%, in vitro fertilization (IVF) is in urgent need for improvements, especially in view of the increasing trend in postponing childbirth in developed societies. Abnormal contraction of the uterus may underlie impaired fertility and unsuccessful IVF. However, currently, there is no method for quantitative assessment of uterine activity and guidance of dedicated intervention. Analysis of the electrohysterogram (EHG) has been extensively used in pregnancy for quantifying uterine contractions. In this paper, we evaluate, for the first time, the use of EHG analysis for characterizing contractions in women in two different phases of the menstrual cycle, when the uterus is expected to be active and quiescent. In this preliminary study, by estimating the time evolution of the EHG signal energy, we derive the contraction frequency, fC, as a possible marker for quantifying the activity of the uterus and discriminate between active and quiescent status. Ultrasound (US) image sequences are simultaneously recorded and visually analyzed for a qualitative validation of the results. The high correlation (0.91) between fC obtained by EHG and US analysis and the measured different values of fC in the two phases motivate further research to confirm the value of EHG analysis for contraction quantification in nonpregnant women.

Criteria for failed labor induction have not been standardized. The increasing prevalence of labor induction and the lack of a definition for failed induction contribute to unnecessary abdominal deliveries. Labor duration, cervical dilation, and uterine activity necessary to attain the active phase are reviewed. A practical definition of failed induction of labor is suggested.