Electrical Uterine Myography Research Articles

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

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

370: Non-invasive Uterine Monitoring: Comparison of Electrical Uterine Myography (EUM) and Intrauterine Pressure Catheter (IUPC)

To validate the accuracy and clinical usefulness of the EUM device by comparing it with simultaneous use of IUPC among laboring patients. This was a prospective observational study of laboring women at Montefiore Medical Center from February 2017 to April 2018. Inclusion criteria: maternal age >18 years old, singleton pregnancy, gestational age > 24 weeks. Exclusion criteria: allergy to silver, implanted electronic device and irritated skin/open wound on the abdominal wall. Patients were monitored simultaneously with the EUM device, EUM300 (OB Tools, Migdal HaEmek, Israel), and by IUPC for at least 30 minutes. Two blinded obstetricians reviewed the tracings. The primary outcome of the study was continuous, interpretable tracing and secondary outcomes were total number of contractions, onset of contractions and duration of contractions. Based on McNemar’s test to compare proportion of discontinuity between the two methods, enrolling 55 patients provided 80% power to detect an odds ratio of 3.2 with a two-sided type I error rate of 5%. A total of 68 patients were monitored for 2,749 minutes via simultaneous EUM and IUPC devices: 55 (80.8%) patients were obese. 56 (82.35%) of the patients were receiving oxytocin at the time of the recordings and 67 (98.5%) had epidurals. On average, the EUM was no different with regards to interpretability/continuity when compared to IUPC on a 30-minute tracing (Effect estimate 0.95 (CI= -0.18, 2.08) p=0.10). This finding was similar among obese and nonobese women [Effect estimate 0.50 (CI=0.19, 1.19) p=0.16 and Effect estimate 2.85 (CI= -2.16, 7.85) p=0.27, respectively]. Overall, EUM was no different in its ability to detect contractions among obese and non-obese patients [Effect estimate 1.06 (CI= .99, 1.13) p=0.11 and Effect estimate 1.12 (CI=0.95, 1.33) p=0.17, respectively]. 84% of the patients preferred the EUM device over the IUPC. We were unable to demonstrate a difference between when EUM and IUPC monitoring with regards to interpretability and contraction frequency regardless of maternal obesity. Given that the EUM device is noninvasive and can also monitor contraction strength, future noninferiority studies should be conducted to determine if the EUM device can replace IUPC monitoring.

371: Non-invasive Uterine Monitoring: Comparison of Electrical Uterine Myography (EUM) and Tocodynamometry (TOCO) among Obese Parturients

To validate the accuracy of an external device which monitors uterine electrical activity by comparing it to tocodynamometry among obese patients. This was a prospective observational study of laboring women at Montefiore Medical Center from February 2017 to April 2018. Inclusion criteria: maternal age >18 years old, singleton pregnancy, gestational age > 24 weeks and BMI >/= 30 kg/m2. Exclusion criteria: allergy to silver, implanted electronic device of any kind and irritated skin or open wound on the abdominal wall. Patients were monitored simultaneously with the EUM device, EUM300 (OB Tools, Migdal HaEmek, Israel), and by TOCO for at least 30 minutes. Two blinded obstetricians reviewed the tracings. The primary outcome of the study was continuous, interpretable tracing and secondary outcomes were total number of contractions, timing of onset of contractions and duration of contractions. Based on McNemar’s test to compare proportion of discontinuity between the two methods, enrolling 55 patients provided 80% study power to detect an odds ratio of 3.2 with a two-sided type I error rate of 5%. A total of 65 obese patients were monitored via simultaneous EUM and TOCO devices. The average gestational age was 39.0 weeks with 43 (66.15%) patients in latent labor. 35 (53.85%) patients were receiving oxytocin at the time of the recordings and 45 (69.3%) patients had epidural. On average, the EUM was 1.49 minutes (CI= 0.62, 2.37) more interpretable/continuous in a 30 min tracing (p=0.001). Overall, EUM detected 39% (CI= 23%, 57%) more contractions in a 30 min tracing compared to TOCO (p<0.0001). With regards to patient preference, 42 (64.62%) patients undergoing simultaneous monitoring preferred the EUM device over the TOCO. Given the challenges of using a tocodynomameter with obese women, consideration should be given to replacing it with the EUM device, which appears to be more sensitive and accurate and preferred by patients.

Uterine electrical activity, oxytocin and labor: translating electrical into mechanical.

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+0weeks) 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 30min before oxytocin initiation and until at least four contractions per 10min 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<0.001). Mean and minimum (but not maximum) uterine electrical activity during oxytocin infusion correlated with the baseline uterine activity. The delta EUM index was not significantly affected by demographic or obstetric parameters. There was no correlation between the delta EUM index and time to delivery or the mean EUM index during oxytocin administration and time to delivery. Uterine electrical activity as evaluated by EUM is significantly intensified following oxytocin administration, regardless of obstetrical characteristics, and is correlated with the baseline uterine electrical activity prior to oxytocin infusion.

Uterine electrical activity at labor: is there a correlation between labor stages?

Objective: To determine the association between the myometrial electrical activity in the active and second stages of labor at term using electrical uterine myography (EUM).Methods: A prospective observational study of 47 singleton deliveries at term in a tertiary hospital. All women were assessed using noninvasive 9-channel surface electrodes of the EUM during labor. EUM index (EUMi) was calculated as the mean electrical activity during a 30 min monitoring period and expressed as microjouls (MJ). Mean EUMi of the active and second stages of labor were compared accordingly.Results: Mean EUMi during the active phase was 3.53 ± 0.43 MJ, whereas mean EUMi in the second stage was 3.66 ± 0.48 MJ (p = 0.02). Correlation analysis between mean EUMi of the active and second stages of labor produced r2 = 0.68 (p < 0.01). In a regression analysis model EUMi of the active stage of labor remained strongly correlated with the duration of the second stage (r2 = 0.73, p < 0.001). No correlation was found between EUMi and the duration of the second stage.Conclusion: A positive correlation of myometrial electrical activity exists between active phase and second stage of labor. However, while EUMi was associated with the duration of the active phase, no correlation was found between EUMi and the duration of the second stage.

Factors affecting uterine electrical activity during the active phase of labor prior to rupture of membranes

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.

Does artificial rupturing of membranes in the active phase of labor enhance myometrial electrical activity?

Objective: To determine whether artificial rupture of membranes (AROM) during active phase of labor augments uterine contractility using Electrical Uterine Myography (EUM).Study design: A prospective study of 31 women with term singleton pregnancy during active phase of labor. Using a non-invasive EUM technique, electrical uterine activity was recorded in the 30 min preceding AROM and in the immediate 30 min thereafter. Augmentation was defined as >5% increase in EUM index between the basal and post-AROM states, representing the mean EUM increase of the entire cohort. Low basal uterine contraction was defined as EUM index of less than the entire cohort median result prior AROM (3.5 micro-Watt-Second (mWS)).Results: Mean dilatation in which AROM was preformed was 5.5 ± 1.8 cm. There was a significant increase in mean EUM measurement in the post-AROM compared to the basal state (3.59 ± 0.39 versus 3.42 ± 0.47 mWS, p < 0.001). In multivariate analysis, low BMI and low basal uterine contractions were the only significant predictors for augmentation following AROM (OR 0.69, 95% C.I 0.45–0.97, p = 0.009 and OR 16.03, 95% CI 1.90–134.69, p = 0.003, respectively).Conclusion: Myometrial electrical activity was significantly enhanced following AROM. Augmentation was mostly pronounced in patients with lower BMI and initial lower basal uterine contraction.

582: Can electrical uterine myography predict who will benefit from artificial rupture of membranes (AROM)?

582: Can electrical uterine myography predict who will benefit from artificial rupture of membranes (AROM)?

Uterine electric activity during the third stage of labor; a look into the physiology of a deserted stage

Objective: To evaluate uterine activity during the third stage of labor and compare it to that observed in the second stage of labor.Study design: Uterine electric activity was prospectively measured using electrical uterine myography (EUM) in 44 women with singleton pregnancy at term during the final 30 min of the second stage and throughout the third stage of labor. Results are reported using a scoring index of 1–5 mWS (micro-Watt-Second). Patients were stratified into two groups based on the duration of the third stage (<15 min and >=15 min)Results: The mean durations of the second and third stages were 51.9 ± 63.5 and 15.4 ± 7.5 minutes, respectively. During the third stage, uterine activity (contractions peaks) was similar to that observed during the second stage of labor (3.43 ± 0.64 mWS versus 3.42 ± 0.57 mWS, p = 0.8). No correlation was found between the duration of the third stage and EUM measurements during the third (p = 0.9) or the second (p = 0.2) stages of labor. No association was found between EUM measurements during the third stage and parity, maternal age, fetal weight, duration of labor, gestational age, gravity or BMI. The rate of oxytocin use during the second stage and EUM measurements during the second or third stage did not differ among women with short versus long duration of the third stage.Conclusion: Uterine activity during the third stage is comparable and as intense as that occurring during the second stage. Third stage length cannot be predicted by contraction intensity during the second or third stage of labor.

78: Uterine electrical activity during administration of tractocile (atosiban) in preterm labor

Traditional uterine contractions measurement has low PPV, for prediction of preterm delivery. Controversy exists concerning tocolytic efficacy. We aimed to evaluate uterine activity in preterm labor, under administration of Tractocile (Atosiban), using a novel device that records electrical uterine myography (EUM).

A new method for assessing uterine activity: Haran et al

See related article, page 412 While external tocodynamometry is useful in gauging the frequency and duration of contractions, the intrauterine pressure catheter (IUPC) determines these more accurately and also measures contraction intensity. However, because the IUPC is invasive, its use is best reserved for selected patients, including women who are obese or who are having an inadequate response to oxytocin. An innovative system not yet available in the United States might overcome the drawbacks of both methods, proving useful in all patients. Studies to date suggest the electrical uterine myography monitor (OB-Tools, Migdal Ha’emek, Israel), which pairs novel technology software and a device, detects contraction onset, time to peak, frequency, duration, and intensity. In short, the electrical activity that drives uterine contractions is captured with 9 electrodes—placed in 3 rows and 3 columns around the mother’s umbilicus— and a multichannel amplifier. The software then deciphers the signals and renders a contraction wave that can be analyzed for relevant parameters. In a new study, Haran and colleagues evaluated the technique against the IUPC, currently the gold standard for tracking uterine activity.

A comparison of surface acquired uterine electromyography and intrauterine pressure catheter to assess uterine activity

Intrauterine pressure catheter (IUPC) is the primary device used to evaluate uterine activity. In contrast to the IUPC, electrical uterine myography (EUM) enables noninvasive measurement of frequency, intensity, and tone of contractions. The aim of this study was to determine the accuracy of EUM compared to IUPC. EUM measured myometrial electrical activity using a multichannel amplifier and a noninvasive position sensor. In all, 47 women in labor were monitored simultaneously with an IUPC and EUM. We compared the frequency, intensity, and tone of uterine contractions between the methods. The correlation of the frequency, intensity, and tone of contractions between uterine electromyography and IUPC was strong with significant r values of 0.808-1 (P < .0001). Electrical uterine electromyography yields information about uterine contractility comparable to that obtained with IUPC.

706: Electrical uterine myography (EUM) is as good as intra uterine pressure catheter (IUP) in measuring contractions

706: Electrical uterine myography (EUM) is as good as intra uterine pressure catheter (IUP) in measuring contractions

Can myometrial electrical activity identify patients in preterm labor?

The objective of the study was to determine whether myometrial electrical activity can differentiate false from true preterm labor. Electrical uterine myography (EUM) was measured prospectively on 87 women, gestational age less than 35 weeks. The period between contractions, power of contraction peaks and movement of center of electrical activity (RMS), was used to develop an index score (1-5) for prediction of preterm delivery (PTD) within 14 days of the test. The score was compared with fetal fibronectin (fFN) and cervical length (CL). Patients delivering within 14 days from testing showed a higher index and mean RMS (P = .000). No patients with EUM index scores of 1-2 delivered in this time frame. Combining EUM with CL or fFN increased predictability. Logistic regression revealed that history of PTD and EUM index had 4- to 5-fold increased risk for PTD. Gestational age at testing, body mass index, fFN, and CL were nonsignificant contributors to PTD risk. Measuring myometrial electrical activity may enhance identification of patients in true premature labor.