Search

Introduction: The updated intrapartum cardiotocography (CTG) classification system by FIGO in 2015 (FIGO2015) and the FIGO2015-approached classification by the Swedish Society of Obstetricians and Gynecologist in 2017 (SSOG2017) are not harmonized with the fetal ECG ST analysis (STAN) algorithm from 2007 (STAN2007). The study aimed to reveal homogeneity and agreement between the systems in classifying CTG and ST events, and relate them to maternal and perinatal outcomes., Material and Methods: Among CTG traces with ST events, 100 traces originally classified as normal, 100 as suspicious and 100 as pathological were randomly selected from a STAN database and classified by two experts in consensus. Homogeneity and agreement statistics between the CTG classifications were performed. Maternal and perinatal outcomes were evaluated in cases with clinically hidden ST data (n = 151). A two-tailed p < 0.05 was regarded as significant., Results: For CTG classes, the heterogeneity was significant between the old and new systems, and agreements were moderate to strong (proportion of agreement, kappa index 0.70-0.86). Between the new classifications, heterogeneity was significant and agreements strong (0.90, 0.92). For significant ST events, heterogeneities were significant and agreements moderate to almost perfect (STAN2007 vs. FIGO2015 0.86, 0.72; STAN2007 vs. SSOG2017 0.92, 0.84; FIGO2015 vs. SSOG2017 0.94, 0.87). Significant ST events occurred more often combined with STAN2007 than with FIGO2015 classification, but not with SSOG2017; correct identification of adverse outcomes was not significantly different between the systems., Conclusion: There are discrepancies in the classification of CTG patterns and significant ST events between the old and new systems. The clinical relevance of the findings remains to be shown., (© 2017 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

Objective: Each pregravidic, gestational or intrapartum complication may, per se, have a different impact on the operative delivery rate, regardless of which fetal monitoring system was adopted. We wanted to verify if CTG plus ST interval analysis (STAN) of fetal ECG might be able to reduce the number of operative delivery for fetal distress in high-risk pregnancies compared to low-risk women monitored with CTG alone., Materials and Methods: In this cohort study, we evaluated 100 high-risk pregnancies consecutively with STAN® S31 (Neoventa Medical, Gotenburg, Sweden) and 160 low-risk pregnancies consecutively with continuous CTG (Hewlett Packard, 50 IP, Palo Alto, CA)., Results: We found that STAN monitoring, although associated with a higher total operativity rate, both vaginal (11% versus 3.12%, p = 0.015) and cesarean (17% versus 4.37%, p = 0.001), reduced the cesarean section rate performed for fetal distress (29.41% versus 85.71%, p = 0.023) compared with low-risk CTG monitoring group., Conclusion: CTG plus ST interval analysis of fetal ECG reduced the risk of operative cesarean delivery for fetal distress in high-risk gestations.

Cardiotocography (CTG) is a technique used to monitor intrapartum fetal condition and is one of the most common obstetric procedures. Second line methods of fetal monitoring have been developed in an attempt to reduce unnecessary interventions due to continuous cardiotocography and to better identify fetuses at risk of intrapartum asphyxia. The acid-base balance of the fetus is evaluated by fetal blood scalp samples, the modification of the myocardial oxygenation by the fetal ECG ST-segment analysis (STAN) and the autonomic nervous system by the power spectral analysis of the fetal heart variability. To correctly interpret the features observed on CTG traces or second line methods, it seems important to understand normal physiology during labor and the compensatory mechanisms of the fetus in case of hypoxemia. Therefore, the aim of this review is first to describe fetal physiology during labor and then to explain the modification of the second line monitoring during labor., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Objective: Maternal obesity affects one in every five women giving birth worldwide. This condition is associated with adverse perinatal outcomes, as well as increased morbidity and mortality for mother and offspring., Methods: We carried out a prospective study at the University of Pecs Medical Center, Pecs, Hungary, between 1 January 2013 and 1 January 2014. We enrolled 60 obese (body mass index >30 kg/m(2)) low-risk pregnant women and 108 age-, ethnicity-, and parity-matched nonobese pregnant control subjects. The ST segment of the fetal electrocardiogram was assessed by STAN® monitoring. Neonatal outcomes and cord gas analysis of the umbilical vessels were evaluated after birth., Results: No infant with definitive metabolic acidosis was delivered in either group. We observed 32 and 106 ST events in the obese and control group, respectively, but this difference was not statistically significant. To date, none of the infants delivered as part of this study have demonstrated developmental insufficiency., Conclusions: Obesity might not influence the fetal electrocardiogram during labor as an independent risk factor for adverse pregnancy outcomes. Studies with larger cohort sizes are needed to confirm our findings.

Objective: To investigate whether use of ST analysis of the fetal electrocardiogram (STan) as an adjunct to continuous cardiotocography (CTG) reduces the rate of emergency Cesarean section (EmCS) compared with CTG alone. Methods: This was a randomized controlled trial of patients with a singleton fetus in cephalic presentation at ≥ 36 weeks' gestation, requiring continuous electronic fetal monitoring during labor at a tertiary maternity hospital in Adelaide, Australia, between January 2018 and July 2021. Participants were randomized to undergo CTG + STan or CTG alone. The calculated sample size was 1818 participants. The primary outcome was EmCS. Secondary outcomes included metabolic acidosis, a composite adverse perinatal outcome, and other maternal and neonatal morbidity and safety outcomes. Results: The present study enrolled 970 women, of whom 967 were included in the primary analysis. EmCS occurred in 107/482 (22.2%) deliveries in the CTG + STan arm and in 107/485 (22.1%) in the CTG arm (adjusted relative risk, 1.02 (95% CI, 0.81–1.27); P = 0.89). There was no difference in the rate of adverse maternal or neonatal outcomes between arms. Conclusions: The addition of STan as an adjunct to continuous CTG did not reduce the EmCS rate. The smaller‐than‐anticipated sample size meant that this study was underpowered to detect absolute differences of ≤ 5% and, therefore, this negative finding could be due to a Type‐2 error. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to investigate if intrapartum monitoring with cardiotocography (CTG) in combination with ST analysis (STAN) results in an improved perinatal outcome. Methods: We performed a two-center randomized trial. 1013 women with term fetuses in cephalic presentation entered the trial. If a CTG showed intermediate or pathological abnormalities, they were offered fetal blood sampling (FBS) and inclusion if the pH value was above 7.25. They were randomized to either CTG + FBS or CTG + STAN. The primary outcome was neonatal metabolic acidosis, defined as umbilical cord arterial blood pH below 7.05, and base excess equal to or below −10. The secondary outcomes included operative vaginal delivery for fetal distress. Results: The rate of metabolic acidosis was 0.8% in the CTG + FBS group and 1.5% in women in the CTG + STAN (P = 0.338). More women in the CTG + STAN group delivered by operative vaginal delivery (25.6% vs 33.5%, P = 0.006). Significantly fewer women in the CTG + STAN group had three to five (28.8% vs 11.0%, P = < 0.001) and six to ten fetal blood samples taken (3.4% vs 0.4%, P = < 0.001). Conclusion: CTG + STAN did not reduce the incidence of neonatal metabolic acidosis compared to CTG + FBS. CTG + STAN was, however, associated with an increased risk of operative vaginal delivery and a reduced use of FBS. If STAN is used for fetal surveillance, we recommend that it is combined with other methods, such as FBS, for confirmation of the need for operative delivery. Clinicaltrials.gov ID: NCT01699646. Date of registration: October 4, 2012 (retrospectively registered). https://clinicaltrials.gov/ct2/show/NCT01699646?id=NCT01699646&draw=2&rank=1 [ABSTRACT FROM AUTHOR]

Introduction: Recent developments have produced new CTG classification systems and the question is to what extent these may affect the model of FHR + ST interpretation? The two new systems (FIGO2015 and SSOG2017) classify FHR + ST events differently from the current CTG classification system used in the STAN interpretation algorithm (STAN2007). Aim: Identify the predominant FHR patterns in connection with ST events in cases of cord artery metabolic acidosis missed by the different CTG classification systems. Indicate to what extent STAN clinical guidelines could be modified enhancing the sensitivity. Provide a pathophysiological rationale. Material and methods: Forty-four cases with umbilical cord artery metabolic acidosis were retrieved from a European multicenter database. Significant FHR + ST events were evaluated post hoc in consensus by an expert panel. Results: Eighteen cases were not identified as in need of intervention and regarded as negative in the sensitivity analysis. In 12 cases, ST changes occurred but the CTG was regarded as reassuring. Visual analysis of the FHR + ST tracings revealed specific FHR patterns: Conclusion: These findings indicate FHR + ST analysis may be undertaken regardless of CTG classification system provided there is a more physiologically oriented approach to FHR assessment in connection with an ST event. [ABSTRACT FROM AUTHOR]

Intrapartum cardiotocography (CTG) has a high false-positive rate. This has contributed to the rapid increase in obstetric interventions without a strong improvement in perinatal outcomes. We explore the role of ST analysis (STAN®) as an adjunct to CTG in identifying fetal asphyxia during labor. We conclude that STAN® reduces the rate of fetal blood sampling and instrumental vaginal deliveries, and has the potential to reduce the number of Australian operative interventions without compromising neonatal outcome. [ABSTRACT FROM PUBLISHER]

Key content ST analysis ( STAN) involves a combination of fetal heart rate interpretation and analysis of the fetal electrocardiogram., STAN has been available for over 5 years in the UK and is used in some, but not all, maternity units., STAN aims to reduce the incidence of fetal acidaemia and hypoxia by identifying these earlier and with greater sensitivity than cardiotocography ( CTG) alone., Learning objectives To be familiar with the background theory and evidence for the use of STAN., To learn the principles for interpretation of the STAN trace., To review practical tips for STAN application and use of STAN monitors., Ethical issues STAN interpretation is currently not part of the RCOG curriculum for obstetrics and gynaecology trainees., Trainees may rotate to a unit that uses STAN routinely and be expected to participate in its use with minimal training. [ABSTRACT FROM AUTHOR]

Five randomized controlled trials have been published on intrapartum fetal heart rate monitoring with ST analysis of the fetal electrocardiogram, but the debate on its usefulness has not yet been ended. We consider ST analysis a useful and cost-effective addition to conventional fetal heart rate monitoring. We will provide support for this opinion by discussing the pathophysiology of ST changes in relation to fetal asphyxia, the results of the randomized controlled trials and numerous meta-analyses of these randomized controlled trials and trends in fetal outcome in hospitals in different countries following the introduction of the ST technology in the labor ward. [ABSTRACT FROM AUTHOR]

Objectives: This paper describes a methodology for the monitoring of the fetal cardiac health status during pregnancy, through the effective and non-invasive monitoring of the abdominal ECG signals (abdECG) of the mother.Methods: For this purpose, a three-stage methodology has been developed. In the first stage, the fetal heart rate (fHR) is extracted from the abdECG signals, using nonlinear analysis. Also, the eliminated ECG (eECG) is calculated, which is the abdECG after the maternal QRSs elimination. In the second stage, a blind source separation technique is applied to the eECG signals and the fetal ECG (fECG) is obtained. Finally, monitoring of the fetus is implemented using features extracted from the fHR and fECG, such as the T/QRS ratio and the characterization of the fetal ST waveforms.Results: The methodology is evaluated using a dataset of simulated multichannel abdECG signals: 94.79% accuracy for fHR extraction, 92.49% accuracy in T/QRS ratio calculation and 79.87% in ST waveform classification.Conclusions: The novel non-invasive proposed methodology is advantageous since it offers automated identification of fHR and fECG and automated ST waveform analysis, exhibiting a high diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Objective To assess the cost-effectiveness of the use of cardiotocography (CTG) complemented with fetal electrocardiography and ST analysis compared with the use of CTG alone in term deliveries when a decision has been made to use fetal monitoring with a scalp electrode. Design A cost-effectiveness analysis based on a probabilistic decision model incorporating relevant strategies and lifelong outcomes. Setting Maternity wards in Sweden. Population Women with term fetuses after a clinical decision had been made to apply a fetal scalp electrode for internal CTG. Methods A decision model was used to compare the costs and effects of two different treatment strategies. Baseline estimates were derived from the literature. Discounted costs and quality-adjusted life years (QALYs) were simulated over a lifetime horizon using a probabilistic model. Main outcome measures QALYs, incremental costs, and cost per QALY gained expressed as incremental cost-effectiveness ratio (ICER). Results The analysis found an incremental effect of 0.005 QALYs for ST analysis compared with CTG; the ST analysis strategy was also moreover associated with a €56 decrease in costs, thus dominating the CTG strategy. The probability that ST analysis is cost-effective in comparison with CTG is high, irrespective of the willingness-to-pay value for a QALY. Conclusions Compared with CTG alone, ST analysis is cost-effective when used in term high-risk deliveries in which there is a need for internal fetal monitoring. [ABSTRACT FROM AUTHOR]

Objective To assess the occurrence of ST-interval segment changes of the fetal electrocardiogram (ECG) and cardiotocographic (CTG) abnormalities preceding acidaemia at birth. Design Case–control study. Setting University hospital labour ward. Sample Newborns with severe cord artery metabolic acidaemia (pH < 7.00 and lactate ≥ 10 mmol/l; n= 24), moderate metabolic acidaemia (pH 7.00–7.09 and lactate ≥ 10; n= 48), acidaemia (pH 7.00–7.09; n= 52), pre-acidaemia (pH 7.10–7.19; n= 265), and controls (pH ≥ 7.20; n= 117). Methods Monitoring traces were assessed blinded to outcome. Main outcome measures CTG and ST changes. Results Any ST event occurred significantly more often among cases with severe (79%) and moderate (75%) metabolic acidaemia than among controls (50%). The difference was restricted to baseline T/QRS rises and to the second stage of labour, during which any event only occurred significantly more often among cases with severe metabolic acidaemia (62%) than among controls (38%). ST events coincided with abnormal CTG patterns in 67, 44, 40, and 28% of cases with severe and moderate metabolic acidaemia, acidaemia, and pre-acidaemia, respectively, and in 12% of controls. ST events with intermediary CTG were similarly frequent in the case groups (0–6%) as in the controls (4%). The ST guidelines stated intervention in 96, 62, 73, and 49% of case groups and 23% of controls. Conclusions Only two of three cases with severe and less than half of cases with moderate metabolic acidaemia were preceded by ST events coinciding with CTG abnormalities. It is therefore important to intervene for long-lasting, rapidly deteriorating or marked (preterminal) CTG abnormalities, also in the absence of ST events. [ABSTRACT FROM AUTHOR]

Objective. The objective of our study was to test the hypothesis that the availability and selective use of STAN® in conjunction with cardiotocography for intrapartum monitoring, lowers the incidence of operative deliveries for fetal distress. Design. Observational study. Setting. Delivery suite of the National University Hospital, Singapore. Methods. The data regarding intrapartum cesarean sections and instrumental vaginal deliveries for presumed fetal distress and the condition of the neonate at birth (Apgar scores at one and five minutes and admission to neonatal intensive care unit (NICU) were collected over two consecutive three-year periods. In the first triennium, only external cardiotocography was used for intrapartum fetal surveillance and in the second triennium STAN® monitoring was available for use in the delivery suite. Results. With the availability and selective use of STAN® monitoring, there was a significant decrease in the number of instrumental deliveries for fetal distress (from 66 out of 520 (0.9%) to 36 out of 474 (0.5%), p<0.025), the number of admissions to the NICU (from 418 (5.6%) to 311 (4.6%), p<0.01) and the number of neonates with Apgar score of seven or less at five minutes (from 192 (2.6%), p<0.001 to 113 (1.7%), p<0.001). There was no significant difference in the incidence of emergency cesarean sections for fetal distress during the two time periods. Conclusion. Intrapartum monitoring of term fetuses with cardiotocography combined with selective use of ST analysis leads to a significant reduction in the number of operative deliveries for suspected fetal distress with no adverse effect on neonatal outcome. [ABSTRACT FROM AUTHOR]

Objective: To determine the diagnostic value of fetal ST-segment analysis (STAN) in predicting neonatal acidosis.Methods: The STAN S21 was used to monitor singleton fetuses in labor with abnormal FHR. Physicians later reviewed tracings to identify any ST events dictating intervention. Outcome measures were umbilical artery pH< or =7.15 and pH< or =7.05 at birth. The sensitivity, specificity, PPV, and NPV of a significant ST event to predict both outcomes were calculated.Results: Analysis included 411 women. Sensitivity of a significant ST event for screening pH< or =7.15 (21.9%) was 38% (41/108), specificity 83% (252/303), PPV 45% (41/92) and NPV 79% (252/319), and for pH< or =7.05, it was (3.4%), 62.5% (10/16), 79% (313/395), 11% (10/92), and 98% (313/319), respectively.Conclusion: In a population with abnormal FHR in labor, STAN sensitivity is moderate (almost 40%) for predicting pH< or =7.15 and better (almost 60%) for more severe acidosis (pH< or =7.05). [ABSTRACT FROM AUTHOR]

Objective To examine whether intrapartum monitoring by means of automatic ST analysis (STAN) of fetal electrocardiography could reduce the rate of neonatal acidemia and the rate of operative intervention during labour, compared with monitoring by means of cardiotocography (CTG). Design Randomised controlled trial. Setting Labour ward in tertiary-level university hospital. Sample A total of 1483 women in active labour with singleton term fetus in cephalic presentation. Methods Women were randomly assigned to be monitored either by STAN or by CTG. Fetal blood sampling (FBS) was optional in both groups. Main outcome measures Neonatal acidemia (umbilical artery pH <7.10), neonatal metabolic acidosis (umbilical artery pH <7.05 and base excess <-12 mmol/l) and operative interventions: caesarean section rate, vacuum outlet (VO) rate and FBS rate. Results There were no statistically significant differences between the STAN group and CTG group in the incidence of neonatal acidemia (5.8 versus 4.7%) or metabolic acidosis (1.7 versus 0.7%). The caesarean section rate (6.4 versus 4.7%) and the VO rate (9.5 versus 10.7%) were also similar in the STAN and CTG groups. The incidence of FBS was lower (P < 0.001) in the STAN group (7.0%) than in the CTG group (15.6%). Conclusions Intrapartum fetal monitoring by means of automatic STAN did not improve the neonatal outcome or decrease the caesarean section rate. However, the need for FBS during labour was lower in the STAN group. [ABSTRACT FROM AUTHOR]

Background: Fetal pulse oximetry measures arterial oxygen saturation during delivery. The fetal electrocardiogram STAN S21 analyzes the repolarisation segment of ECG (ST) waveform, which is altered by the intramyocardial potassium release resulting from metabolic acidemia. This study aimed to evaluate the feasibility of a simultaneous application of pulse oximetry and fetal electrocardiography and to estimate any agreement between both methods indicating fetal compromise.Methods: In an observational trial 35 fetuses were simultaneously monitored by pulse oximetry (OBS-500) and electrocardiography. The evaluation focused on signal output and on the coincidence of desaturation in fetal pulse oximetry and on ST events. Desaturation was defined as a drop of at least 20% of oxygen saturation from base line level occurring within 1 min (steep desaturation) or duration of time (s) with oxygen saturation below the threshold of 30%. Statistical analysis was performed with the Mann-Whitney U-test for continuous variables.Results: Signal output of the simultaneous application of both sensors was not significantly reduced in the electrocardiogram and in pulse oximetry (8% vs. 12% reduction). In 15 of the 35 fetuses, ST events indicating fetal hypoxia occurred. In these cases, pulse oximetry showed significantly more episodes of desaturation in comparison with fetuses without ST events. Median saturation during the ST events was significantly lower than in the recordings without ST events (60% vs. 74%, p < 0.05). In the umbilical artery these neonates showed significantly lower pH (7.19 vs. 7.33, p < 0.001), significantly higher lactate (5.1 vs. 3.4 mmol/l, p < 0.05) and significantly lower base deficit (-9.4mmol/l vs. -4.0 mmol/l, p < 0.001) levels.Conclusions: The combination of fetal pulse oximetry and fetal electrocardiography appears feasible and indicates signs of intermittent hypoxia. These findings may encourage the development of technology that combines these different methods of monitoring. [ABSTRACT FROM AUTHOR]

Background: Cardiotocography is almost ubiquitous in its use in intrapartum care. Although it has been demonstrated that there is some benefit from continuous intrapartum fetal monitoring using cardiotocography, there is also an increased risk of caesarean section which is accompanied by short-term and long-term risks to the mother and child. There is considerable potential to reduce unnecessary operative delivery with up to a 60% false positive diagnosis of fetal distress using cardiotocography alone. ST analysis of the fetal electrocardiogram is a promising adjunct to cardiotocography alone, and permits detection of metabolic acidosis of the fetus, potentially reducing false positive diagnosis of fetal distress.Methods: This study will be a single-centre, parallel-group, randomised controlled trial, conducted over 3 years. The primary hypothesis will be that the proportion of women with an emergency caesarean section on ST analysis will not equal that for women on cardiotocography monitoring alone. Participants will be recruited at the Women's and Children's Hospital, a high-risk specialty facility with approximately 5000 deliveries per annum. A total of 1818 women will be randomised to the treatment or conventional arm with an allocation ratio of 1:1, stratified by parity. The primary outcome is emergency caesarean section (yes/no). Statistical analysis will follow standard methods for randomised trials and will be performed on an intention-to-treat basis. Secondary maternal and neonatal outcomes will also be analysed. Additional study outcomes include psychosocial outcomes, patient preferences and cost-effectiveness.Discussion: Approximately 20% of Australian babies are delivered by emergency caesarean section. This will be the first Australian trial to examine ST analysis of the fetal electrocardiogram as an adjunct to cardiotocography as a potential method for reducing this proportion. The trial will be among the first to comprehensively examine ST analysis, taking into account the impact on psychosocial well-being as well as cost-effectiveness. This research will provide Australian evidence for clinical practice and guideline development as well as for policy-makers and consumers to make informed, evidence-based choices about care in labour.Trial Registration: ANZCTR, ACTRN1261800006268 . Registered on 19 January 2018. [ABSTRACT FROM AUTHOR]