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

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

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

Diagnostic accuracy of the partograph alert and action lines to predict adverse birth outcomes: a systematic review.

BACKGROUND: There are questions about the use of the 'one-centimetre per hour rule' as a valid benchmark for assessing the adequacy of labour progress. OBJECTIVES: To determine the accuracy of the alert (1-cm/hour) and action lines of the cervicograph in the partograph to predict adverse birth outcomes among women in first stage of labour. SEARCH STRATEGY: PubMed, EMBASE, CINAHL, POPLINE, Global Health Library, and reference lists of eligible studies. SELECTION CRITERIA: Observational studies and other study designs reporting data on the correlation between the alert line status of women in labour and the occurrence of adverse birth outcomes. DATA COLLECTION AND ANALYSIS: Two reviewers at a time independently identified eligible studies and independently abstracted data including population characteristics and maternal and perinatal outcomes. MAIN RESULTS: Thirteen studies in which 20 471 women participated were included in the review. The percentage of women crossing the alert line varied from 8 to 76% for all maternal or perinatal outcomes. No study showed a robust diagnostic test accuracy profile for any of the selected outcomes. CONCLUSIONS: This systematic review does not support the use of the cervical dilatation over time (at a threshold of 1 cm/h during active first stage) to identify women at risk of adverse birth outcomes. TWEETABLE ABSTRACT: Alert line of partograph does not identify women at risk of adverse birth outcomes.

Comparing the performance of a new disposable pneumatic tocodynamometer with a standard tocodynamometer.

INTRODUCTION: The goal was to test a newly developed pneumatic tocodynamometer (pTOCO) that is disposable and lightweight, and evaluate its equivalence to the standard strain gauge-based tocodynamometer (TOCO). MATERIAL AND METHODS: The equivalence between the devices was determined by both mechanical testing and recording of contractile events on women. The data were recorded simultaneously from a pTOCO prototype and standard TOCO that were in place on women who were undergoing routine contraction monitoring in the Labor and Delivery unit at the University of Arkansas for Medical Sciences. In this prospective equivalence study, the output from 31 recordings on 28 pregnant women that had 171 measureable contractions simultaneously in both types of TOCO were analyzed. The traces were scored for contraction start, peak and end times, and the duration of the event was computed from these times. RESULTS: The response curve to loaded weights and applied pressure were similar for both devices, indicating their mechanical equivalence. The paired differences in times and duration between devices were subjected to mixed-models analysis to test the pTOCO for equivalence with standard TOCOs using the two-one-sided tests procedure. The event times and duration analyzed simultaneously from both TOCO types were all found to be significantly equivalent to within ±10 s (all p-values ≤0.0001). CONCLUSION: pTOCO is equivalent to the standard TOCO in the detection of the timing and duration of uterine contractions. pTOCO would provide a lightweight, disposable alternative to commercially available standard TOCOs.

Home uterine monitoring for detecting preterm labour.

BACKGROUND: 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. OBJECTIVES: 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 conventional or other care packages that do not include home uterine monitoring. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2014), CENTRAL (The Cochrane Library 2014, Issue 8), MEDLINE (1966 to 31 August 2014), EMBASE (1974 to 31 August 2014), CINAHL (1982 to 31 August 2014) and scanned reference lists of retrieved studies. SELECTION CRITERIA: Randomised control trials of home uterine activity monitoring, with or without patient education programmes, for women at risk for preterm birth, in comparison to the same care package without home uterine activity monitoring. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We did not attempt to contact authors to resolve queries. MAIN RESULTS: There were 15 included studies (total number of enrolled participants 6008); 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, n = 1596; fixed-effect analysis) (GRADE high). The significant 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 significant difference in the rate of perinatal mortality (RR 1.22; 95% CI 0.86 to 1.72; two studies, n = 2589) (GRADE low)There was no significant difference in the number of preterm births at less than 37 weeks (average RR 0.85; CI 0.72 to 1.01; eight studies, n = 4834; random-effects, T² = 0.03, I² = 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, n = 2367; random-effects, T² = 0.02, I² = 32%) (GRADE moderate). The difference was not statistically significant when only high quality studies were included (RR 0.86; 95% CI 0.74 to 1.01; one study, n = 1292). Women using home uterine monitoring made more unscheduled antenatal visits (mean difference (MD) 0.49; 95% CI 0.39 to 0.62; two studies, n = 3707) (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, n = 4316; random-effects. T² = 0.03, I² = 62%) but this difference was no longer significant when the analysis was restricted to higher quality studies (average RR 1.22; 95% CI 0.90 to 1.65, three studies, n = 3749,random-effects, T² = 0.05, I² = 76%) (GRADE low). One small study reported that the home uterine monitoring group spent fewer days in hospital antenatally. No data on maternal anxiety or acceptability were found. AUTHORS' CONCLUSIONS: Home uterine monitoring may result in fewer admissions to a neonatal intensive care unit but more unscheduled antenatal visits and tocolytic treatment, but the level of evidence is generally low to moderate. Important group differences were not evident when sensitivity analysis was undertaken using only high quality trials. There is no impact on maternal and perinatal outcomes such as perinatal mortality or incidence of preterm birth.

Labor progress indices and dynamics of the individual uterine contraction during the active stage of labor.

AIM: To obtain and study new data on the dynamics of the labor process and to develop a contraction-based index of labor progress. METHODS: This study was carried out at the Delivery Room, Department of Obstetrics and Gynecology, Western Galilee Hospital, Nahariya, Israel, using a new device (Birth Track). We continuously monitored cervical dilatation (CD) and head descent (HD) in 30 nulliparaous women during active labor with (augmented group) and without (study group) oxytocin augmentation. This led to the development and validation of progress indices based on features extracted from continuous monitoring. RESULTS: There were no significant differences between the average of each parameter in the study and augmented groups, except for HD velocity. Average HD velocity was faster in the study group. Linear regression analyses demonstrated that head station (HS) amplitude and Toco amplitude were the best parameters for predicting HD velocity in both groups. In the study group, average HD velocity was also significantly related to Toco rate and contraction efficiency. In the augmented group, only a weak correlation with Toco rate was seen, and no correlation with contraction efficiency. CONCLUSION: With the assistance of the Birth Track device, we can obtain continuous data on the labor process and indices to estimate the labor progress process without the use of vaginal (manual) examination.

Outcomes after internal versus external tocodynamometry for monitoring labor.

BACKGROUND: It has been hypothesized that internal tocodynamometry, as compared with external monitoring, may provide a more accurate assessment of contractions and thus improve the ability to adjust the dose of oxytocin effectively, resulting in fewer operative deliveries and less fetal distress. However, few data are available to test this hypothesis. METHODS: We performed a randomized, controlled trial in six hospitals in The Netherlands to compare internal tocodynamometry with external monitoring of uterine activity in women for whom induced or augmented labor was required. The primary outcome was the rate of operative deliveries, including both cesarean sections and instrumented vaginal deliveries. Secondary outcomes included the use of antibiotics during labor, time from randomization to delivery, and adverse neonatal outcomes (defined as any of the following: an Apgar score at 5 minutes of less than 7, umbilical-artery pH of less than 7.05, and neonatal hospital stay of longer than 48 hours). RESULTS: We randomly assigned 1456 women to either internal tocodynamometry (734) or external monitoring (722). The operative-delivery rate was 31.3% in the internal-tocodynamometry group and 29.6% in the external-monitoring group (relative risk with internal monitoring, 1.1; 95% confidence interval [CI], 0.91 to 1.2). Secondary outcomes did not differ significantly between the two groups. The rate of adverse neonatal outcomes was 14.3% with internal monitoring and 15.0% with external monitoring (relative risk, 0.95; 95% CI, 0.74 to 1.2). No serious adverse events associated with use of the intrauterine pressure catheter were reported. CONCLUSIONS: Internal tocodynamometry during induced or augmented labor, as compared with external monitoring, did not significantly reduce the rate of operative deliveries or of adverse neonatal outcomes. (Current Controlled Trials number, ISRCTN13667534; Netherlands Trial number, NTR285.)

Monitoring uterine activity during labor: a comparison of 3 methods.

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.

Internal versus external tocodynamometry during induced or augmented labour.

BACKGROUND: 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. OBJECTIVES: To assess the effectiveness of IT compared with using ET when intravenous oxytocin is used for induction or augmentation of labour. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2013) and PubMed (1966 to 6 April 2013). SELECTION CRITERIA: 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. DATA COLLECTION AND ANALYSIS: 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. MAIN RESULTS: 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). AUTHORS' CONCLUSIONS: 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.

Internal versus external tocodynamometry during induced or augmented labour.

BACKGROUND: 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. OBJECTIVES: To assess the effectiveness of IT compared with using ET when intravenous oxytocin is used for induction or augmentation of labour. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (11 April 2012) and PubMed (1966 to 7 March 2012). SELECTION CRITERIA: 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. DATA COLLECTION AND ANALYSIS: 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. MAIN RESULTS: 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). AUTHORS' CONCLUSIONS: 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 during labour--a multi-centre, blinded two-way trial of external tocodynamometry against electrohysterography.

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<0.001). All doctors evaluated the UA assessment as "easier" (p <0.001) using the EHG compared with TOCO. CONCLUSION: Intrapartum UA monitoring in -daily practice via the EHG mode provides a more recognisable UA trace than the TOCO.

Rapid assessment of partograph utilisation in selected maternity units in Kenya.

BACKGROUND: Prolonged labour causes maternal and perinatal morbidity and mortality. Its sequela include obstructed labour, uterine rupture, maternal exhaustion, postpartum haemorrhage, puerperal sepsis, obstetric fistula, stillbirths, birth asphyxia and neonatal sepsis. These complications can be reduced by using the partograph to assess the progress of labour. The Ministry of Health, Kenya has adopted this tool for labour management in the country and the standardised partograph is recommended for use in all delivery units. OBJECTIVE: To determine the utilisation of the partograph in the management of labour in selected health facilities in Kenya. DESIGN: A descriptive cross sectional study. SETTING: Nine health facilities -ranging from a tertiary hospital to health centre, including public private and faith based facilities in four provinces in Kenya. RESULTS: All facilities apart from Pumwani Maternity Hospital and one health centre were using the partograph. The correct use was low, the knowledge on the use of the tool was average and there was minimal formal training being provided. Staff shortage was listed as the most common cause of not using the tool. Contractions were recorded 30-80%, foetal heart rate 53-90% and cervical dilatation 70-97%. Documentation of state of the liquor, moulding and descent as well as maternal parameters such as pulse, and blood pressure and urinalysis were minimally recorded. Supplies for monitoring labour such as fetoscopes and blood pressure machines were in short supply and sometimes not functional. Overall, the poor usage was contributed to staff shortages, lack of knowledge especially on interpretation of findings, negative attitudes, conflict between providers as to their roles in filling the partograph, and senior staff themselves not acting as role models with regards to the use, advocacy and implementation of the partograph. CONCLUSION: The partograph was available in most units. However, accurate recording of parameters to monitor the foetus, the mother and progress of labour as recommended was mostly not done. Shortage of staff, lack of knowledge, lack of team work, lack of supplies and negative attitude among healthcare providers were some of the obstacles noted to hamper partograph use.

Contractions: Traditional concepts and their role in modern obstetrics.

Contractions are produced through a complex interplay of hormonal, mechanical, and electrical factors. In labor, contractions are measured using the Montevideo unit. Clinical considerations in labor wherein contraction assessment becomes paramount include the care of women whose labor is complicated by abnormal progress or tachysystole. In an era of obstetrics in which the high cesarean rate is a major issue of concern, there remain many questions as to how to best incorporate contraction monitoring into practice in order to optimize care. Technological advancement has led to the development on new modalities that can be used to study contraction physiology, and there may be an opportunity in the future to apply these methods for use in the clinical setting. This article also makes a case for the need to reevaluate the current measures of uterine contractile activity and the definition of contraction adequacy using updated definitions of normal labor progress.

New electrohysterogram-based estimators of intrauterine pressure signal, tonus and contraction peak for non-invasive labor monitoring.

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 = 14.61 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). 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 well-being.

Development of Electrohysterogram Recording System for Monitoring Uterine Contraction.

Uterine contraction (UC) is an important clinical indictor for monitoring uterine activity. The purpose of this study is to develop a portable electrohysterogram (EHG) recording system (called PregCare) for monitoring UCs with EHG signals. The PregCare consisted of sensors, a signal acquisition device, and a computer with application software. Eight-channel EHG signals, the tocodynamometry (TOCO) signal, and maternal perception were recorded simultaneously by the signal acquisition device controlled by the computer via Bluetooth. PregCare was firstly evaluated by a signal simulator. Its relative error (RE) and coefficient of variation (CV) were calculated, and its agreement with the commercial instrument PowerLab was assessed by Bland-Altman plots. After that, PregCare was applied to 20 pregnant women in a hospital to record their EHG signals. These EHG signals were preprocessed and segmented into UCs and non-UCs. Then, the EHG features corresponding to UCs and non-UCs were extracted, respectively, including power spectral density (PSD), root mean square (RMS), peak frequency (PF), median frequency (MDF), and sample entropy (SamEn). One-way ANOVA was employed to assess the difference between UCs and non-UCs. The results show that RE and CV were less than 8% and 0.03%, respectively, which indicated the high accuracy and repeatability of PregCare. The small differences of mean and standard deviation indicated the high agreement between PregCare and PowerLab. Besides, the PSD of UCs was much larger than non-UCs between 0 and 0.7 Hz. RMS of UCs was significantly larger than non-UCs (p < 0.05). PF and SamEn of UCs were significantly smaller than non-UCs (p < 0.05). In conclusion, the developed EHG recording system was able to record EHG signals reliably. It has the advantages of portability, low power consumption, and wireless transmission, which can be used for long-term monitoring of UCs and prediction of the preterm delivery.

Waterproofing EMG Instrumentation.

While still experimental, measurement of external uterine electromyographic (EMG) activity is a more sensitive and noninvasive method for measuring uterine contractility in human labor than the methods currently used in clinical practice. Hydrotherapy is purported to improve contractility in labor, yet there have been no reports of abdominal uterine EMG activity measured during immersion. To test telemetric EMG equipment and different waterproofing techniques under dry and immersed conditions, the authors recorded surface EMG activity from the abdominal muscles of 11 healthy, nonpregnant women, 22 to 51 years of age. After attaching one pair of electrodes to the skin on either side of the umbilicus and applying the waterproofing material, the authors tested the signal by asking participants to perform a short series of leg lifts while seated in a chair to evoke abdominal muscle contractions. They were then immersed to the chest in a hydrotherapy tub while performing two to three leg lifts over 60 s every 5 min for 60 min with 20 lb of weight suspended from their ankles to counteract the buoyancy effect of water. EMG activity was continuously recorded. They then repeated the dry-measures sequence. While waterproofing remained intact, EMG signals were essentially unchanged between dry and wet conditions. Of the 11 waterproofing applications tested, 10 failed at some point. In the data from the successful application, EMG signals in both channels exhibited stable baselines throughout and an absence of low-frequency artifact. The development of this technique allows for the recording of external uterine EMG activity during hydrotherapy. The authors have begun using it to investigate the effects of hydrotherapy on uterine contractility during human labor.

Medical devices; obstetrical and gynecological devices; classification of computerized labor monitoring system. Final rule.

The Food and Drug Administration (FDA) is classifying the computerized labor monitoring systems into class II (special controls). Elsewhere in this issue of the Federal Register, FDA is announcing the availability of a guidance document entitled, "Guidance for Industry and FDA Staff; Class II Special Controls Guidance Document: Computerized Labor Monitoring Systems," which will serve as the special controls for these devices. The agency is classifying these devices into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of these devices.

Clinical assessment of uterine contractions.

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.

Prediction of intrauterine pressure waveform from transabdominal electrohysterography.

OBJECTIVE: We investigated the ability to non-invasively obtain uterine electromyograms (EMG; electrohysterogram (EHG)) to predict the intrauterine pressure (IUP) waveform. STUDY DESIGN: Patients enrolled in a term labor study of trans-abdominal electrical activity, who underwent IUP monitoring for obstetric indication, were included in this study (n=14). EHG signals were processed and prediction filters trained against the IUP from the same patient. Sixty-eight 10-minute traces each of EHG and IUP waveforms were reviewed (Montevideo unit (MVU) calculation) by two experienced labor nurses and one obstetrician, blinded to patient and EHG vs. IUP output. In addition, area under the contraction curve (AUC), contraction detection and duration were compared. RESULTS: EHG-derived MVUs statistically correlated with IUP (r=0.795; p < 0.0001), but mathematically differed by 17+/-20% with 83% of EHG MVUs underestimating the IUP. The coefficients of variation between the two methods were relatively high ( approximately 20%), and these could not be substantially corrected via calibration. AUC differed by 8+/-19% with 69% of EHG-derived AUC underestimating the IUP. EHG detected 98% of 362 IUP contractions, with 8% over-detection. Contraction duration was similar: 56.4+/-11.9 s vs. 55.7+/-13.0 s, for IUP and EHG, respectively. CONCLUSION: EHG-based contraction monitoring approximates IUP monitoring for contraction detection and duration. The correlation with contraction height (MVU) and AUC is much weaker with the investigated signal-processing algorithm.

Vaginal electrohysterography: the design and preliminary evaluation of a novel device for uterine contraction monitoring in an ovine model (.).

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Technical characteristics of current cardiotocographic monitors.

Cardiotocographic (CTG) monitors are complex electronic devices developed to acquire, process and display foetal heart rate (FHR) and uterine contraction (UC) signals. This chapter describes the main characteristics of current CTG monitors, in order to allow a better understanding of the technology. An ultrasound transducer is used for the external monitoring of FHR signals, whereas a tocodynamometer is used for the external monitoring of UCs. These technologies are recommended for routine clinical use in both the antepartum and intrapartum periods. Foetal electrode and intrauterine pressure sensors provide internal monitoring of FHR and UC signals, respectively, which are more precise than external signals. They are only applicable during labour, after cervical dilatation and ruptured membranes, and they have established contraindications. The registration of foetal movements, simultaneous monitoring of twins and triplets, continuous maternal heart rate monitoring, monitoring of other maternal parameters, alarms, digital outputs and telemetry are other available characteristics in some CTG monitors.