Monitoring uterine activity during labor: a comparison of 3 methods Euliano, Tammy Y., MD; Nguyen, Minh Tam, MS; Darmanjian, Shalom, PhD ...
American journal of obstetrics and gynecology,
2013, January 2013, 2013-Jan, 2013-01-00, 20130101, Letnik:
208, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Objective Tocodynamometry (Toco; strain gauge technology) provides contraction frequency and approximate duration of labor contractions but suffers frequent signal dropout, necessitating ...repositioning by a nurse, and may fail in obese patients. The alternative invasive intrauterine pressure catheter (IUPC) is more reliable and adds contraction pressure information but requires ruptured membranes and introduces small risks of infection and abruption. Electrohysterography (EHG) reports the electrical activity of the uterus through electrodes placed on the maternal abdomen. This study compared all 3 methods of contraction detection simultaneously in laboring women. Study Design Upon consent, laboring women were monitored simultaneously with Toco, EHG, and IUPC. Contraction curves were generated in real-time for the EHG, and all 3 curves were stored electronically. A contraction detection algorithm was used to compare frequency and timing between methods. Seventy-three subjects were enrolled in the study; 14 were excluded due to hardware failure of 1 or more of the devices (n = 12) or inadequate data collection duration (n = 2). Results In comparison with the gold-standard IUPC, EHG performed significantly better than Toco with regard to the Contractions Consistency Index (CCI). The mean CCI for EHG was 0.88 ± 0.17 compared with 0.69 ± 0.27 for Toco ( P < .0001). In contrast to Toco, EHG was not significantly affected by obesity. Conclusion Toco does not correlate well with the gold-standard IUPC and fails more frequently in obese patients. EHG provides a reliable noninvasive alternative, regardless of body habitus.
The partograph (sometimes known as partogram) is usually a pre-printed paper form on which labour observations are recorded. The aim of the partograph is to provide a pictorial overview of labour, ...and to alert midwives and obstetricians to deviations in maternal or fetal well-being and labour progress. Charts have traditionally contained pre-printed alert and action lines. An alert line, which is based on the slowest 10% of primigravid women's labours, signifies slow progress. An action line is placed a number of hours after the alert line (usually two or four hours) to prompt effective management of slow progress of labour.This review is an update of a review last published in 2013.
The primary objective was to determine the effectiveness and safety of partograph use on perinatal and maternal morbidity and mortality. The secondary objective was to determine which partograph design is most effective for perinatal and maternal morbidity and mortality outcomes.
We searched Cochrane Pregnancy and Childbirth's Trials Register (31 August 2017), ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (31 August 2017) and reference lists of retrieved studies.
Randomised, cluster-randomised, and quasi-randomised controlled trials involving a comparison of partograph use with no partograph, or comparison between different partograph designs.
Three review authors independently assessed eligibility, quality and extracted data. When one review author was also the trial author, the two remaining review authors assessed the studies independently. We assessed the evidence using the GRADE approach.
We have included 11 studies, involving 9475 women in this review; three studies assessed partograph use versus no partograph, seven assessed different partograph designs, and one assessed partograph use versus labour scale. Risk of bias varied in all studies. It was infeasible to blind staff or women to the intervention. Two studies did not adequately conceal allocation. Loss to follow-up was low in all studies. We assessed the evidence for partograph use versus no partograph using the GRADE approach; downgrading decisions were due to study design, inconsistency, indirectness, and imprecision of effect estimates.Most trials reported caesarean section rates and Apgar scores less than 7 at five minutes; all other outcomes were not consistently reported (e.g. duration of first stage of labour and maternal experience of childbirth).Partograph versus no partograph (3 trials, 1813 women)It is uncertain whether there is any clear difference between partograph use and no partograph in caesarean section rates (average risk ratio (RR) 0.77, 95% confidence interval (CI) 0.40 to 1.46; n = 1813; 3 trials; I² = 87%; very low-quality evidence); oxytocin augmentation (RR 1.02, 95% CI 0.95 to 1.10; n = 1156; 1 trial; moderate-quality evidence); duration of first stage of labour (mean difference (MD) 0.80 hours, 95% CI -0.06 to 1.66; n = 1156; 1 trial; low-quality evidence); or Apgar score less than 7 at five minutes (RR 0.76, 95% CI 0.29 to 2.03; n = 1596; 2 trials; I² = 87%; very low-quality evidence).Partograph with different placement of action lines (4 trials, 5051 women)When compared to a four-hour action line, women in the two-hour action line group were more likely to receive oxytocin augmentation (average RR 2.44, 95% CI 1.36 to 4.35; n = 4749; 4 trials; I² = 96%). There was no clear difference in caesarean section rates (RR 1.06, 95% CI 0.88 to 1.28; n = 4749; 4 trials); duration of first stage of labour (RR 0.81 hours, 95% CI 0.32 to 2.04; n = 948; 1 trial); maternal experience of childbirth (average RR 0.61, 95% CI 0.28 to 1.35; n = 2269; 2 trials; I² = 83%); or Apgar score less than 7 at five minutes (RR 0.93, 95% CI 0.61 to 1.42; n = 4749; 4 trials) between the two- and four-hour action line.The following comparisons only include data from single studies. Fewer women reported negative childbirth experiences in the two-hour action line group compared to the three-hour action line group (RR 0.49, 95% CI 0.27 to 0.90; n = 348; 1 trial). When we compared the three- and four-hour action line groups, the caesarean section rate was higher in the three-hour action line group (RR 1.70, 95% CI 1.07 to 2.70; n = 613; 1 trial). We did not observe any clear differences in any of the other outcomes in these comparisons.Partograph with alert line only versus partograph with alert and action line (1 trial, 694 women)The caesarean section rate was lower in the alert line only group (RR 0.68, 95% CI 0.50 to 0.93). There were no clear differences between groups for oxytocin augmentation, low Apgar score, instrumental vaginal birth and perinatal death.Partograph with latent phase (composite) versus partograph without latent phase (modified) (1 trial, 743 women)The caesarean section and oxytocin augmentation rates were higher in the partograph with a latent phase (RR 2.45, 95% CI 1.72 to 3.50; and RR 2.18, 95% CI 1.67 to 2.83, respectively). There were no clear differences between groups for oxytocin augmentation, and Apgar score less than 7 at five minutes.Partograph with two-hour action line versus partograph with stepped dystocia line (1 trial, 99 women)Fewer women received oxytocin augmentation in the dystocia line group (RR 0.62, 95% CI 0.39 to 0.98). We did not observe any clear differences in any of the other primary outcomes in this comparison.Partograph versus labour scale (1 trial, 122 women)The use of the partograph compared with the labour scale resulted in fewer women receiving oxytocin augmentation (RR 0.32, 95% CI 0.18 to 0.54), but did not produce any clear differences for any of the other primary outcomes.
On the basis of the findings of this review, we cannot be certain of the effects of routine use of the partograph as part of standard labour management and care, or which design, if any, are most effective. Further trial evidence is required to establish the efficacy of partograph use per se and its optimum design.
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 Objective Current uterine monitoring techniques have major drawbacks that could be avoided when using electrohysterography for uterine monitoring. Recently, a new electrohysterography method ...has been developed, providing a real-time tocogram on standard cardiotocography monitors. The diagnostic characteristics of this novel method need to be determined and compared to conventional methods We hypothesised that electrohysterography can perform better than external tocodynamometry due to the adhesive properties of the contact electrodes (less motion sensitive), and the improved signal acquisition through subcutaneous tissue (less obesity sensitive). Study design In this prospective diagnostic accuracy study, uterine contractions of labouring women were simultaneously monitored by three different monitoring techniques: electrohysterography, external tocodynamometry, and intra-uterine pressure catheter as method of reference. We performed a two-hour measurement during first and/or second stage of term labour. The contractions of each method were automatically detected by a computer-based algorithm. As the applied method had not been described in literature before, an interim analysis was performed to minimise exposure to the invasive pressure catheter. The main outcome parameter was the sensitivity of electrohysterography in comparison to external tocodynamometry for uterine contraction detection, tested by the Wilcoxon signed rank test. Results Uterine contractions of 48 term labouring women were simultaneously monitored by electrohysterography, external tocodynamometry, and intra-uterine pressure catheter. The study was terminated after the interim analysis as the sensitivity of electrohysterography was significantly higher compared to external tocodynamometry: median 89.5% (interquartile range (IQR); 82–93) and 65.3% (IQR; 53–81) respectively, p < 0.001. In a subgroup analysis of obese women ( n = 15), the sensitivity of electrohysterography was significantly higher than external tocodynamometry (median 88.4% (IQR; 79–95) and 45.8% (IQR; 38–61) respectively, p < 0.001). Whereas in a subanalysis of second stage of labour ( n = 8), electrohysterography did not perform better than external tocodynamometry (median 72.8% (IQR; 61–87) and 66.4% (IQR; 46–75) respectively, p = 0.225). Electrohysterography registered 0.4 more contractions per 10 minutes than the intra-uterine pressure measurement ( p < 0.001) and 0.5 more contractions per 10 minutes than external tocodynamometry ( p < 0.001). Conclusion Electrohysterography has a higher sensitivity for uterine contraction detection than external tocodynamometry during first stage of labour, in non-obese and obese women. Electrohysterography identifies more contractions than conventional techniques.
The objective of this paper is to evaluate the novel method for analyzing the nonlinear correlation of the uterine electromyography (EMG). The application of this method may improve monitoring in ...pregnancy, labor detection, and preterm labor detection. Uterine EMG signals recorded from a 4 × 4 matrix of electrodes on the subjects' abdomen are used here. The propagation was analyzed using the nonlinear correlation coefficient h 2 . Signals from 49 women (36 during pregnancy and 13 in labor) at different gestational age were used. ROC curves were computed to evaluate the potential of three methods to differentiate between 174 contractions recorded during pregnancy and 115 contractions recorded during labor. The results indicate considerably better performance of the nonlinear correlation analysis (area under curve = 0.85) when compared to classical frequency parameters (area under curve = 0.76 and 0.66) in distinguishing labor contractions from normal pregnancy contractions. We conclude that the analysis of the propagation of the uterine electrical activity using the nonlinear correlation coefficient h 2 is a promising way of improving the usefulness of uterine EMG signals for clinical purposes, such as monitoring in pregnancy, labor detection, and prediction of preterm labor.
Clinical assessment of uterine contractions Cohen, Wayne R.
International journal of gynecology and obstetrics,
November 2017, 2017-Nov, 2017-11-00, 20171101, Letnik:
139, Številka:
2
Journal Article
Recenzirano
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.
Techniques for assessing contractions present different advantages and limitations. Intrauterine pressure reflects labor progress unreliably; electrohysterography is well placed to become the standard technique.
We investigate motion mode (M-mode) ultrasound scan as a potential non-invasive uterine monitoring technique and compare its contraction characteristics with external tocodynamometry (TOCO). This ...prospective diagnostic accuracy study included 39 term pregnant woman in active spontaneous labor. M-mode and TOCO were simultaneously performed and uterine contraction characteristics and consistency were compared quantitatively and visually. The results identified a 71.5% ± 35.3% uterine wall thickening during uterine contractions on M-mode. Uterine monitoring with M-mode had a consistency rate of 88.7% ± 6.9% with conventional TOCO method. During 20-min monitoring, the number of detected contractions was significantly higher (p < 0.001) in M-mode (8.2 ± 1.2) than TOCO (7.4 ± 1.5). As for the mean value of the duration of a contraction (seconds), it was significantly shorter (p < 0.001) in M-mode (38.5 ± 3.5) than TOCO (49.2 ± 4.1). For M-mode, the number of detected contractions had a negative but insignificant correlation with the body mass index (BMI) (r = - 0.25 - 0.52, 0.07, p = 0.127) and the subcutaneous tissue thickness (STT) (r = - 0.21 - 0.49, 0.11, p = 0.200). As for TOCO, the contractions had a negative and significant correlation with BMI (r = - 0.41 - 0.64, - 0.11, p = 0.009) and negative and insignificant correlation with STT (r = - 0.26 - 0.54, 0.06, p = 0.104). The evidence suggests that contraction detection with M-mode is a promising non-invasive technique for uterine monitoring. The preliminary analysis finds that contraction detection is not affected by BMI or STT. With future sensitivity studies, and improvements in image-processing and software technologies, the proposed technique promises to be a viable alternative to existing techniques, especially for obese patients.
Uterine contractions can be registered by external tocodynamometry (ET) or, after rupture of the membranes, by internal tocodynamometry (IT). Monitoring of the frequency of contractions is important ...especially when intravenous oxytocin is used as excessive uterine activity (hyperstimulation or tachysystole) can cause fetal distress. During induction of labour as well as during augmentation with intravenous oxytocin, some clinicians choose to monitor frequency and strength of contractions with IT rather than with ET as an intrauterine pressure catheter measures intrauterine activity more accurately than an extra-abdominal tocodynamometry device. However, insertion of an intrauterine catheter has higher costs and also potential risks for mother and child.
To assess the effectiveness of IT compared with using ET when intravenous oxytocin is used for induction or augmentation of labour.
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2013) and PubMed (1966 to 6 April 2013).
We included all published randomised controlled trials with data from women in whom IT was compared with ET in induced or augmented labour with oxytocin. We excluded trials that employed quasi-randomised methods of treatment allocation. We found no unpublished or ongoing studies on this subject.
Two review authors independently assessed trial eligibility and risk of bias, and independently extracted data. Data were checked for accuracy. Where necessary, we contacted study authors for additional information.
Three studies involving a total of 1945 women were included. Overall, risk of bias across the three trials was mixed. No serious complications were reported in the trials and no neonatal or maternal deaths occurred. The neonatal outcome was not statistically different between groups: Apgar score less than seven at five minutes (RR 1.78, 95% CI 0.83 to 3.83; three studies, n = 1945); umbilical artery pH less than 7.15 (RR 1.31, 95% CI 0.95 to 1.79; one study, n = 1456); umbilical artery pH less than 7.16 (RR 1.23, 95% CI 0.39 to 3.92; one study, n = 239); admission to the neonatal intensive care unit (RR 0.34, 95% CI 0.07 to 1.67; two studies, n = 489); and more than 48 hours hospitalisation (RR 0.92, 95% CI 0.71 to 1.20; one study, n = 1456). The pooled risk for instrumental delivery (including caesarean section, ventouse and forceps extraction) was not statistically significantly different (RR 1.05, 95% CI 0.91 to 1.21; three studies, n = 1945). Hyperstimulation was reported in two studies (n = 489), but there was no statistically significant difference between groups (RR 1.21, 95% CI 0.78 to 1.88).
This review found no differences between the two types of monitoring (internal or external tocodynamometry) for any of the maternal or neonatal outcomes. Given that this review is based on three studies (N = 1945 women) of moderate quality, there is insufficient evidence to recommend the use of one form of tocodynamometry over another for women where intravenous oxytocin was administered for induction or augmentation of labour.
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.
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).
The continuous pressure global model yielded IUP estimates with Cpe = 14.61 mm Hg, MPe = 29.17 mm Hg and Toe = 7.8 mm Hg. The adaptive models significantly reduced errors to CPe = 11.88, MPe = 16.02 and Toe = 5.61 mm 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).
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 well-being.
To reduce the morbidity and mortality associated with preterm birth, home uterine activity monitoring aims for early detection of increased contraction frequency, and early intervention with ...tocolytic drugs to inhibit labour and prolong pregnancy. However, the effectiveness of such monitoring is disputed.
To determine whether home uterine activity monitoring is effective in improving the outcomes for women and their infants considered to be at high risk of preterm birth, when compared with care that does not include home uterine activity monitoring.
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 June 2016), CENTRAL (Cochrane Library 2016, Issue 5), MEDLINE (1966 to 28 June 2016), Embase (1974 to 28 June 2016), CINAHL (1982 to 28 June 2016), and scanned reference lists of retrieved studies.
Randomised control trials of home uterine activity monitoring, with or without patient education programmes, for women at risk of preterm birth, compared with care that does not include home uterine activity monitoring.
Two review authors independently assessed trials for inclusion and risks of bias, extracted data and checked them for accuracy. We did not attempt to contact authors to resolve queries. We assessed the evidence using the GRADE approach.
There were 15 included studies (6008 enrolled participants); 13 studies contributed data. Women using home uterine monitoring were less likely to experience preterm birth at less than 34 weeks (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.62 to 0.99; three studies, 1596 women; fixed-effect analysis) (GRADE high). This difference was not evident when we carried out a sensitivity analysis, restricting the analysis to studies at low risk of bias based on study quality (RR 0.75, 95% CI 0.57 to 1.00; one study, 1292 women). There was no difference in the rate of perinatal mortality (RR 1.22, 95% CI 0.86 to 1.72; two studies, 2589 babies) (GRADE low).There was no difference in the number of preterm births at less than 37 weeks (average RR 0.85, CI 0.72 to 1.01; eight studies, 4834 women; random-effects, Tau
= 0.03, I
= 68%) (GRADE very low). Infants born to women using home uterine monitoring were less likely to be admitted to neonatal intensive care unit (average RR 0.77, 95% CI 0.62 to 0.96; five studies, 2367 babies; random-effects, Tau
= 0.02, I
= 32%) (GRADE moderate). This difference was not maintained when we restricted the analysis to studies at low risk of bias (RR 0.86, 95% CI 0.74 to 1.01; one study, 1292 babies). Women using home uterine monitoring made more unscheduled antenatal visits (mean difference (MD) 0.48, 95% CI 0.31 to 0.64; two studies, 1994 women) (GRADE moderate). Women using home uterine monitoring were also more likely to have prophylactic tocolytic drug therapy (average RR 1.21, 95% CI 1.01 to 1.45; seven studies, 4316 women; random-effects, Tau
= 0.03, I
= 62%), but this difference was no longer evident when we restricted the analysis to studies at low risk of bias (average RR 1.22, 95% CI 0.90 to 1.65; three studies, 3749 women; random-effects, Tau
= 0.05, I
= 76%) (GRADE low). The number of antenatal hospital admissions did not differ between home groups (RR 0.91, 95% CI 0.74 to 1.11; three studies, 1494 women (GRADE low)). We found no data on maternal anxiety or acceptability.
Home uterine monitoring may result in fewer admissions to a neonatal intensive care unit but in more unscheduled antenatal visits and tocolytic treatment; the level of evidence is generally low to moderate. Important group differences were not evident when we undertook sensitivity analysis using only trials at low risk of bias. There is no impact on maternal and perinatal outcomes such as perinatal mortality or incidence of preterm birth.
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