Intrapartum electronic fetal heart rate monitoring versus intermittent auscultation: a meta-analysis

Intrapartum cardiotocography with simultaneous maternal heart rate registration improves neonatal outcome

BACKGROUND

Intrapartum cardiotocographic monitoring of fetal heart rate by abdominal external ultrasound transducer without simultaneous maternal heart rate recording has been associated with increased risk of early neonatal death and other asphyxia-related neonatal outcomes. It is unclear, however, whether this increase in risk is independently associated with fetal surveillance method or is attributable to other factors.

OBJECTIVE

This study aimed to compare different fetal surveillance methods and their association with adverse short- and long-term fetal and neonatal outcomes in a large retrospective cohort of spontaneous term deliveries.

STUDY DESIGN

Fetal heart rate and maternal heart rate patterns were recorded by cardiotocography during labor in spontaneous term singleton cephalic vaginal deliveries in the Hospital District of Helsinki and Uusimaa, Finland between October 1, 2005, and September 30, 2023. According to the method of cardiotocography monitoring at birth, the cohort was divided into the following 3 groups: women with ultrasound transducer, women with both ultrasound transducer and maternal heart rate transducer, and women with internal fetal scalp electrode. Umbilical artery pH and base excess values, low 1- and 5-minute Apgar scores, need for intubation and resuscitation, neonatal intensive care unit admission for asphyxia, neonatal encephalopathy, and early neonatal death were used as outcome variables.

RESULTS

Among the 213,798 deliveries that met the inclusion criteria, the monitoring type was external ultrasound transducer in 81,559 (38.1%), both external ultrasound transducer and maternal heart rate recording in 62,268 (29.1%), and fetal scalp electrode in 69,971 (32.7%) cases, respectively. The rates of both neonatal encephalopathy (odds ratio, 1.48; 95% confidence interval, 1.08-2.02) and severe acidemia (umbilical artery pH <7.00 and/or umbilical artery base excess ≤-12.0 mmol/L) (odds ratio, 2.03; 95% confidence interval, 1.65-2.50) were higher in fetuses of women with ultrasound transducer alone compared with those of women with concurrent external fetal and maternal heart rate recording. Monitoring with ultrasound transducer alone was also associated with increased risk of neonatal intubation for resuscitation (odds ratio, 1.22; 95% confidence interval, 1.03-1.44). A greater risk of severe neonatal acidemia was observed both in the ultrasound transducer (odds ratio, 2.78; 95% confidence interval, 2.23-3.48) and concurrent ultrasound transducer and maternal heart rate recording (odds ratio, 1.37; 95% confidence interval, 1.05-1.78) groups compared with those monitored with fetal scalp electrodes. No difference in risk of neonatal encephalopathy was found between newborns monitored with concurrent ultrasound transducer and maternal heart rate recording and those monitored with fetal scalp electrodes.

CONCLUSION

The use of external ultrasound transducer monitoring of fetal heart rate without simultaneous maternal heart rate recording is associated with higher rates of neonatal encephalopathy and severe neonatal acidemia. We suggest that either external fetal heart rate monitoring with concurrent maternal heart rate recording or internal fetal scalp electrode be used routinely as a fetal surveillance tool in term deliveries.

Fetal Heart Rate Auscultation, 4th Edition

Intermittent auscultation (IA) is an evidence-based method of fetal surveillance during labor for birthing people with low-risk pregnancies. It is a central component of efforts to reduce the primary cesarean rate and promote vaginal birth (American College of Obstetricians and Gynecologists, 2019; Association of Women's Health, Obstetric and Neonatal Nurses, 2022a). The use of intermittent IA decreased with the introduction of electronic fetal monitoring, while the increased use of electronic fetal monitoring has been associated with an increase of cesarean births. This practice monograph includes information on IA techniques; interpretation and documentation; clinical decision-making and interventions; communication; education, staffing, legal issues; and strategies to implement IA.

Fetal Heart Rate Auscultation, 4th Edition

Intermittent auscultation (IA) is an evidence-based method of fetal surveillance during labor for birthing people with low-risk pregnancies. It is a central component of efforts to reduce the primary cesarean rate and promote vaginal birth (American College of Obstetricians and Gynecologists, 2019; Association of Women's Health, Obstetric and Neonatal Nurses, 2022a). The use of intermittent IA decreased with the introduction of electronic fetal monitoring, while the increased use of electronic fetal monitoring has been associated with an increase of cesarean births. This practice monograph includes information on IA techniques; interpretation and documentation; clinical decision-making and interventions; communication; education, staffing, legal issues; and strategies to implement IA.

Pathophysiological interpretation of fetal heart rate tracings in clinical practice

The onset of regular, strong, and progressive uterine contractions may result in both mechanical (compression of the fetal head and/or umbilical cord) and hypoxic (repetitive and sustained compression of the umbilical cord or reduction in uteroplacental oxygenation) stresses to a human fetus. Most fetuses are able to mount effective compensatory responses to avoid hypoxic-ischemic encephalopathy and perinatal death secondary to the onset of anaerobic metabolism within the myocardium, culminating in myocardial lactic acidosis. In addition, the presence of fetal hemoglobin, which has a higher affinity for oxygen even at low partial pressures of oxygen than the adult hemoglobin, especially increased amounts of fetal hemoglobin (ie, 180-220 g/L in fetuses vs 110-140 g/L in adults), helps the fetus to withstand hypoxic stresses during labor. Different national and international guidelines are currently being used for intrapartum fetal heart rate interpretation. These traditional classification systems for fetal heart rate interpretation during labor are based on grouping certain features of fetal heart rate (ie, baseline fetal heart rate, baseline variability, accelerations, and decelerations) into different categories (eg, category I, II, and III tracings, "normal, suspicious, and pathologic" or "normal, intermediary, and abnormal"). These guidelines differ from each other because of the features included within different categories and because of their arbitrary time limits stipulated for each feature to warrant an obstetrical intervention. This approach fails to individualize care because the "ranges of normality" for stipulated parameters apply to the population of human fetuses and not to the individual fetus in question. Moreover, different fetuses have different reserves and compensatory responses and different intrauterine environments (presence of meconium staining of amniotic fluid, intrauterine inflammation, and the nature of uterine activity). Pathophysiological interpretation of fetal heart rate tracing is based on the application of the knowledge of fetal responses to intrapartum mechanical and/or hypoxic stress in clinical practice. Both experimental animal studies and observational human studies suggest that, just like adults undertaking a treadmill exercise, human fetuses show predictable compensatory responses to a progressively evolving intrapartum hypoxic stress. These responses include the onset of decelerations to reduce myocardial workload and preserve aerobic metabolism, loss of accelerations to abolish nonessential somatic body movements, and catecholamine-mediated increases in the baseline fetal heart rate and effective redistribution and centralization to protect the fetal central organs (ie, the heart, brain, and adrenal glands), which are essential for intrauterine survival. Moreover, it is essential to incorporate the clinical context (progress of labor, fetal size and reserves, presence of meconium staining of amniotic fluid and intrauterine inflammation, and fetal anemia) and understand the features suggestive of fetal compromise in nonhypoxic pathways (eg, chorioamnionitis and fetomaternal hemorrhage). It is important to appreciate that the timely recognition of the speed of onset of intrapartum hypoxia (ie, acute, subacute, and gradually evolving) and preexisting uteroplacental insufficiency (ie, chronic hypoxia) on fetal heart rate tracing is crucial to improve perinatal outcomes.

Intrapartum cardiotocography: an exploratory analysis of interpretational variation

Our aim was to evaluate the intra- and inter-operator agreement in cardiotocography (CTG) traces analysis using the 2015 FIGO classification guidelines, and whether the educational background and the knowledge of anamnestic data can influence the interpretation of CTG traces. A retrospective interpretation of 73 intrapartum CTGs at time 0 (T0) for a first blind interpretation and at time 1 (T1) two months later with additional anamnestic pregnancy information was made by eight different operators (four obstetricians and four midwives with different years of work experience). The intra-observer agreement demonstrates that midwifes are more concordant than obstetricians with a mean of 77.05% versus a mean of 65.75%. There is moderate inter-observer agreement in classifying a CTG trace as 'normal'; on the contrary, there is no consensus on the 'suspect' and 'pathological' classification category.IMPACT STATEMENTWhat is already known on this subject? Interpretation of intrapartum CTG is affected by significant subjective variables with relevant intra- and inter-observer lack of optimal agreement, especially in case of abnormal o pathologic findings.What do the results of this study add? Clinical data seem to play a role in interpretation of suspicious and pathological traces while they do not affect the rate of agreement for normal traces. Midwives tend to be less influenced by anamnestic data in visual CTG interpretation. Instead, obstetricians tend to be more focussed on clinical data and clinical setting that, as a consequence, tend to have great impact on CTG trace interpretation.What are the implications of these findings for clinical practice and/or further research? Cooperation among obstetricians and between obstetricians and midwives should be encouraged in order to optimise CTG reading and improve maternal and neonatal outcomes. Regarding the influence of clinical parameters in classification of intrapartum CTG traces, especially in case of abnormal CTG traces, it should be conceivable to improve medical skills in CTG blind interpretation and further investigate which clinical parameters are mainly related with an augmented risk of foetal asphyxia and adverse neonatal outcomes.

Methods for Monitoring Risk of Hypoxic Damage in Fetal and Neonatal Brains: A Review

Fetal, perinatal, and neonatal asphyxia are vital health issues for the most vulnerable groups in human beings, including fetuses, newborns, and infants. Severe reduction in oxygen and blood supply to the fetal brain can cause hypoxic-ischemic encephalopathy, leading to long-term neurological disorders, including mental impairment and cerebral palsy. Such neurological disorders are major healthcare concerns. Therefore, there has been a continuous effort to develop clinically useful diagnostic tools for accurately and quantitatively measuring and monitoring blood and oxygen supply to the fetal and neonatal brain to avoid severe consequences of asphyxia Hypoxic-Ischemic Encephalopathy (HIE) and Neonatal Encephalopathy (NE). Major diagnostic technologies used for this purpose include fetal heart rate monitoring (FHRM), fetus scalp blood sampling (FBS), ultrasound (US) imaging, magnetic resonance imaging (MRI), x-ray computed tomography (CT), and nuclear medicine. In addition, given the limitations and shortcomings of traditional diagnostic methods, emerging technologies such as near-infrared spectroscopy (NIRS) and photoacoustic (PA) imaging have also been introduced as stand-alone or complementary solutions to address this critical gap in fetal and neonatal care. This review provides a thorough overview of the traditional and emerging technologies for monitoring fetal and neonatal brain oxygenation status and describes their clinical utility, performance, advantages, and disadvantages.

[S3 guidelines on "full-term vaginal birth" from an anesthesiological perspective : Worthwhile knowledge for anesthesiologists]

The publication of the new S3 guidelines on "full-term vaginal birth" and the guidelines on cesarean section, also published in 2020, provide further steps towards the promotion of evidence-based medicine in obstetrics, even if the exact configuration of neonatal monitoring during birth, in particular, is still the subject of current discussions. The multiprofessionality in the medical supervision of a birth is also fundamentally well-represented in the compilation of the S3 guidelines by the participating actors and specialist societies. Important from an anesthesiological perspective is the fact that neuraxial procedures still represent the gold standard in obstetric analgesia. With remifentanil PCA an alternative option is available that enables a reliable analgesia to be accomplished, e.g. when there are contraindications to performing neuraxial methods, if this is appropriate under the prevailing circumstances (1:1 support and appropriate monitoring). During an uncomplicated birth the strict fasting rules are relaxed. Overall, the guidelines underline the importance of self-determination and self-control for the expectant mother and give the highest priority to the safety and well-being of mother and child; however, this presupposes that the expectant mother is sufficiently informed about the value of neuraxial analgesia. For this it appears to be of importance to initiate information proposals, which go beyond the usual information sessions for parents that are often organized exclusively by midwives.

Obstetric iatrogenesis in the United States: the spectrum of unintentional harm, disrespect, violence, and abuse

'Medical iatrogenesis' was first defined by Illich as injuries 'done to patients by ineffective, unsafe, and erroneous treatments'. Following Lokumage's original usage of the term, this paper explores 'obstetric iatrogenesis' along a spectrum ranging from unintentional harm (UH) to overt disrespect, violence, and abuse (DVA), employing the acronym 'UHDVA' for this spectrum. This paper draws attention to the systemic maltreatment rooted in the technocratic model of birth, which includes UH normalized forms of mistreatment that childbearers and providers may not recognize as abusive. Equally, this paper assesses how obstetric iatrogenesis disproportionately impacts Black, Indigenous, and People of Color (BIPOC), contributing to worse perinatal outcomes for BIPOC childbearers. Much of the work on 'obstetric violence' that documents the most detrimental end of the UHDVA spectrum has focused on low-to-middle income countries in Latin America and the Caribbean. Based on a dataset of 62 interviews and on our personal observations, this paper shows that significant UHDVA also occurs in the high-income U.S., provide concrete examples, and suggest humanistic solutions.

No. 396-Fetal Health Surveillance: Intrapartum Consensus Guideline

OBJECTIVE

To present evidence and recommendations regarding use, classification, interpretation, response, and documentation of fetal surveillance in the intrapartum period and to provide information to help minimize the risk of birth asphyxia while maintaining the lowest possible rate of obstetrical intervention.

INTENDED USERS

Members of intrapartum care teams, including but not limited to obstetricians, family physicians, midwives and nurses, and their learners TARGET POPULATION: Intrapartum women OPTIONS: All methods of uterine activity assessment and fetal heart rate surveillance were considered in developing this document.

OUTCOMES

The impact, benefits, and risks of different methods of surveillance on the diverse maternal-fetal health conditions have been reviewed based on current evidence and expert opinion. No fetal surveillance method will provide 100% detection of fetal compromise; thus, all FHS methods are viewed as screening tests. As the evidence continues to evolve, caregivers from all disciplines are encouraged to attend evidence-based Canadian educational programs every 2 years.

EVIDENCE

Literature published between January 1976 and February 2019 was reviewed. Medline, the Cochrane Database, and international guidelines were used to search the literature for all studies on intrapartum fetal surveillance.

VALIDATION METHODS

The principal and contributing authors agreed to the content and recommendations. The Board of the Society of Obstetricians and Gynaecologists of Canada approved the final draft for publication. The level of evidence has been determined using the criteria and classifications of the Canadian Task Force on Preventive Health Care.

BENEFITS, HARM, AND COSTS

Consistent interdisciplinary use of the guideline, appropriate equipment, and trained professional staff enhances safe intrapartum care. Women and their support person(s) should be informed of the benefits and harms of different methods of fetal health surveillance.

RECOMMENDATIONS

CommunicationSupport During Active LabourPrinciples of Intrapartum Fetal SurveillanceSelecting the Method of Fetal Heart Rate Monitoring: Intermittent Auscultation or Electronic Fetal MonitoringPaper SpeedAdmission AssessmentsEpidural AnalgesiaIntermittent Auscultation in LabourElectronic Fetal Monitoring in LabourClassification of Intrapartum Fetal SurveillanceMaternal Heart RateFetal Health Surveillance Assessment in the Active Second Stage of LabourIntrauterine ResuscitationDigital Fetal Scalp StimulationFetal Scalp Blood SamplingUmbilical Cord Blood GasesDocumentationFetal Surveillance Technology Not RecommendedFetal Health Surveillance Education.

Timing intrapartum management based on the evolution and duration of fetal heart rate patterns

One of the most important challenges in obstetrics is to determine the appropriate time to deliver the fetus without exposing the mother to unnecessary operative interventions. The use of continuous cardiotocography (cCTG) during labor has resulted in dramatic reductions in intrapartum fetal deaths, but fetal central nervous system (CNS) injury and cerebral palsy (CP) rates have remain relatively unchanged as related to the use of cCTG . In our view, this is due to continuing inability to recognize progressive fetal deterioration and intervene promptly prior to the development of fetal CNS injury. Although the 2008 NICHD workshop proposed a 3-tier classification system, most fetuses born with severe (pathologic) acidemia (cord artery pH < 7.00), as well as those who eventually develop CP, will never reach the stage of NICHD Category III fetal heart rate (FHR) pattern. In the present "Clinical Opinion," we promote a concept derived from observations, that the evolution of the FHR changes of the deteriorating fetus can be visually defined by three color "zones" that are clinically recognizable and, therefore, are actionable. In addition, we will review information regarding how long the fetus may be able to tolerate an abnormal FHR pattern before it suffers an adverse perinatal outcome, an area of investigation that has been rarely addressed before. Based on the available evidence, Category III FHR patterns should not be used as screening criteria because of low sensitivity for either fetal CNS injury (45%) or severe (pathologic) fetal acidemia (36-44%). In addition, the duration of the Category III pattern required for the development of severe fetal acidemia is extremely short to allow for a timely preventative operative intervention. On the contrary, the use of our proposed "red" zone, which includes the most advanced stages in the progressive deterioration of Category II patterns and Category III, will identify the overwhelming majority of fetuses who develop severe (pathologic) acidemia (96%) and/or CNS injury during labor (100%); moreover, the detection of fetal jeopardy by the use of the "red" zone occurs much earlier, as compared to using Category III, thus allowing reasonable amount of time for a timely obstetrical intervention. Further research is needed to determine the false positive rate and positive predictive value for a pre-determined period of time in the red zone.

Admission Cardiotocography as a Predictor of Low Apgar Score: An Observational, Cross-Sectional Study

Background and objective Cardiotocography (CTG) has been used more frequently in recent decades to reduce intrapartum fetal mortality rates. The purpose of this study was to determine whether pathological or non-reactive CTG could predict a low Apgar (Appearance, Pulse, Grimace, Activity, and Respiration) score. An abnormal trace would indicate a distressed fetus, whereas a normal trace would indicate a well-oxygenated fetus. Methods This study included a total of 470 women with a gestational period of more than 37 weeks. Based on the results of their CTGs, they were divided into three groups. An emergency cesarean section (CS) was performed if there was any sign of fetal distress on CTG. The Apgar scoring for newborns was recorded in the proforma following delivery. Results The study was carried out at two major tertiary-care hospitals in Pakistan. A reactive CTG was found in more than one-third (39.36%) of the 470 patients. An Apgar score above 8 was obtained by 34.26% of the newborns, while an Apgar score below 8 was obtained by more than half (63.40%). Only 2.34% of newborns had an Apgar score below 6. A third (30.64%) of the patients had grade-1 meconium-stained liquor (MSL), 24.89% had grade-2 MSL, 19.79% had grade-3 MSL, and 24.68% had no MSL. One-third (32.34%) of the neonates were admitted to the neonatal intensive care unit (NICU) shortly after birth. When CTG was pathological or non-reactive, the odds of securing a higher Apgar score decreased by 70.45% (OR: 0.30; 95% CI: 0.20-0.44; p<0.001). Conclusion The main conclusion drawn from this study's findings is that a pathological CTG is an indicator of a low Apgar score.

Non-reassuring fetal heart rate patterns: Is it a risk factor for long- term pediatric cardiovascular diseases of the offspring?

OBJECTIVE

We aimed to study the long-term effect of non-reassuring fetal heart rate (NRFHR) patterns on the risk for subsequent pediatric cardiovascular morbidity of the offspring.

STUDY DESIGN

A population based cohort study, comparing total and different subtypes of cardiovascular morbidity related pediatric hospitalizations among offspring born by caesarean delivery (CD) due to NRFHR versus labor dystocia (failure of labor to progress during the 1st or 2nd stage). The analysis included all singletons born between the years 1999-2014 at a single tertiary regional medical center. Cardiovascular related morbidities included hospitalizations involving a pre-defined set of ICD-9 codes, as recorded in hospital computerized files. Infants with congenital malformations, multiple gestations, vaginal deliveries and vacuum failure were excluded from the analysis. Perinatal mortality cases were excluded from the long-term analysis. A Kaplan-Meier survival curve was used to compare the cumulative cardiovascular morbidity incidence, and a Cox proportional hazards model was used to adjust for confounders.

RESULTS

The study population included 9956 newborns who met inclusion criteria; among them, 5810 (58%) were born by CD due to NRFHR, and 4146 (42%) due to labor dystocia with normal FHR (comparison group). Rate of long- term cardiovascular related hospitalizations was comparable between both groups (0.8% vs. 0.7%, OR 0.9, 95% CI 0.6-1.4, p = 0.664; Kaplan-Meier survival curve p = 0.320(. Using a Cox proportional hazards model, controlling for gestational age, no association was found between NRFHR patterns and the risk for subsequent pediatric cardiovascular morbidity of the offspring (Adjusted HR = 0.8, 95% CI 0.5-1.3, p = 0.376).

CONCLUSION

In our population, NRFHR patterns do not affect the risk of long- term pediatric cardiovascular morbidity of the offspring.

Fetal Heart Rate Tracing Category II: A Broad Category in Need of Stratification

Fetal heart rate (FHR) tracings are classified into 3 categories per the National Institute of Child Health and Human Development guidelines. There exists broad consensus on the recognition and management of categories I and III. However, a category II FHR tracing is considered "indeterminate" and cannot be classified as either reassuring or non-reassuring. Absence of variability and high frequency and increased depth of decelerations are the key determining factors that make a category II tracing non-reassuring and are associated with fetal metabolic acidosis. Periodic category II tracing is present in the majority of normal laboring patients. In the setting of a category II tracing, an initial attempt should be made for in utero resuscitation of the fetus. If the tracing fails to improve over a period of 1 to 2 hours, or the fetal tracing gradually deteriorates, a decision should be made for operative vaginal or cesarean delivery. Category II tracing management algorithms can aid in decision-making in this uncertain clinical scenario. Team training and simulation may improve team performance and have a positive impact on neonatal outcomes.

Quantification of Posterior Risk Related to Intrapartum FIGO 2015 Criteria for Cardiotocography in the Second Stage of Labor

INTRODUCTION

Intrapartum cardiotocography (CTG) was used for several decades to detect a stressed fetus so that delivery can be expedited to prevent birth asphyxia. The main aim of the study was to calculate the risk of neonatal acidemia (pH ≤ 7.10) according to duration of the 2nd stage of labor and occurrence of the International Federation of Gynecology and Obstetrics (FIGO) 2015 CTG classification parameters.

MATERIALS AND METHODS

This was a retrospective case-control study on 552 pregnancies receiving continuous CTG monitoring in labor and immediate hemogasanalysis at birth. Cases with umbilical artery (UA) pH ≤ 7.10 and controls with UA pH ≥ 7.10 were matched for parity and gestational age at delivery, with ratio 1:5. Logistic regression analysis, adjusted for the expected risk in the general population, was used to calculate the baseline risk of UA pH ≤ 7.10 in the absence of any CTG pathological feature and those associated with pathological CTG patterns occurring in the 2nd stage according to FIGO 2015.

RESULTS

Seventy-three cases and 387 controls reached 2nd stage and were included in the analysis. For those reaching 2nd stage, the mean adjusted risk of acidemia associated with nonpathological CTG was 1.6%. Stratification of risk according to duration of the 2nd stage yielded risks of neonatal acidemia of 1.23, 2.08, 5.81, and 15.22% at 30, 60, 120, and 180 min, respectively. Bradycardia >10 min was associated with risk of neonatal acidemia of 9.9 and 15.8% for 2nd-stage durations of 30 and 60 min, respectively. Risks associated with 1 prolonged deceleration >5 min were 6.80, 11.08, 27.0, and 51.0% at 30, 60, 120, and 180 min, respectively. Repetitive late or prolonged decelerations >30 min were associated with risk of neonatal acidemia of 2.43, 4.14, 11.17, and 26.45% at 30, 60, 120, and 180 min, respectively.

CONCLUSION

The risk of neonatal acidemia is directly proportional to duration of the 2nd stage, irrespective of the presence of CTG abnormalities, increasing 12-fold (1.2-15.3%) from 30 to 180 min. Occurrence of FIGO 2015 pathological CTG patterns showed a decreasing impact from bradycardia >10 min to decelerations >5 min, recurrent later or prolonged decelerations >30 min, and nonpathological CTG.

Response to category II tracings: Does anything help?

Electronic fetal monitoring (EFM) is the most commonly used tool to screen for intrapartum fetal hypoxia. Category II EFM is present in over 80% of laboring patients and poses a unique challenge to management given the breadth of EFM features that fall within this category. Certain Category II patterns, such as recurrent late or recurrent variable decelerations, are more predictive of neonatal acidemia than others. A key feature among many published algorithms for Category II management is the use of intrauterine fetal resuscitation techniques including maternal oxygen administration, amnioinfusion, intravenous fluid bolus, discontinuation of oxytocin, and tocolytic administration. The goal of intrauterine resuscitation is to prevent or reverse fetal hypoxia. This is most likely to be successful if the etiology of the Category II EFM pattern is identified and targeted resuscitative measures are performed.

Intrapartum cardiotocograph monitoring and perinatal outcomes for women at risk: Literature review

PROBLEM

Caesarean section rates have risen in high-income countries. One of the potential drivers for this is the widespread use of CTG monitoring.

BACKGROUND

Intrapartum cardiotocograph monitoring is considered to be indicated for women at risk for poor perinatal outcome.

AIM

This systematic literature review with meta-analysis examined randomised controlled trials and non-experimental research to determine whether cardiotocograph monitoring rather than intermittent auscultation during labour was associated with changes in perinatal mortality or cerebral palsy rates for high-risk women.

METHODS

A systematic search for research published up to 2019 was conducted using PubMed, CINAHL, Cochrane, and Web of Science databases. Non-experimental and randomised controlled trial research in populations of women at risk which compared intrapartum cardiotocography with intermittent auscultation and reported on stillbirth, neonatal mortality, perinatal mortality and/or cerebral palsy were included. Relative risks were calculated from extracted data, and meta-analysis of randomised controlled trials was undertaken.

FINDINGS

Nine randomised controlled trials and 26 non-experimental studies were included. Meta-analysis of pooled data from RCTs in mixed- and high-risk populations found no statistically significant differences in perinatal mortality rates. The majority of non-experimental research was at critical risk of bias and should not be relied on to inform practice. Cardiotocograph monitoring during preterm labour was associated with a higher incidence of cerebral palsy.

DISCUSSION

Research evidence failed to demonstrate perinatal benefits from intrapartum cardiotocograph monitoring for women at risk for poor perinatal outcome.

CONCLUSION

There is an urgent need for well-designed research to consider whether intrapartum cardiotocograph monitoring provides benefits.

No. 197b-Fetal Health Surveillance: Intrapartum Consensus Guideline

OBJECTIVE

This guideline provides new recommendations pertaining to the application and documentation of fetal surveillance in the intrapartum period that will decrease the incidence of birth asphyxia while maintaining the lowest possible rate of obstetrical intervention. Pregnancies with and without risk factors for adverse perinatal outcomes are considered. This guideline presents an alternative classification system for antenatal fetal non-stress testing and intrapartum electronic fetal surveillance to what has been used previously. This guideline is intended for use by all health professionals who provide intrapartum care in Canada.

OPTIONS

Consideration has been given to all methods of fetal surveillance currently available in Canada.

OUTCOMES

Short- and long-term outcomes that may indicate the presence of birth asphyxia were considered. The associated rates of operative and other labour interventions were also considered.

EVIDENCE

A comprehensive review of randomized controlled trials published between January 1996 and March 2007 was undertaken, and MEDLINE and the Cochrane Database were used to search the literature for all new studies on fetal surveillance antepartum. The level of evidence has been determined using the criteria and classifications of the Canadian Task Force on Preventive Health Care (Table 1).

SPONSOR

This consensus guideline was jointly developed by the Society of Obstetricians and Gynaecologists of Canada and the British Columbia Perinatal Health Program (formerly the British Columbia Reproductive Care Program or BCRCP) and was partly supported by an unrestricted educational grant from the British Columbia Perinatal Health Program. RECOMMENDATION 1: LABOUR SUPPORT DURING ACTIVE LABOUR: RECOMMENDATION 2: PROFESSIONAL ONE-TO ONE CARE AND INTRAPARTUM FETAL SURVEILLANCE: RECOMMENDATION 3: INTERMITTENT AUSCULTATION IN LABOUR: RECOMMENDATION 4: ADMISSION FETAL HEART TEST: RECOMMENDATION 5: INTRAPARTUM FETAL SURVEILLANCE FOR WOMEN WITH RISK FACTORS FOR ADVERSE PERINATAL OUTCOME: When a normal tracing is identified, it may be appropriate to interrupt the electronic fetal monitoring tracing for up to 30 minutes to facilitate periods of ambulation, bathing, or position change, providing that (1) the maternal-fetal condition is stable and (2) if oxytocin is being administered, the infusion rate is not increased (III-B). RECOMMENDATION 6: DIGITAL FETAL SCALP STIMULATION: RECOMMENDATION 7: FETAL SCALP BLOOD SAMPLING: RECOMMENDATION 8: UMBILICAL CORD BLOOD GASES: RECOMMENDATION 9: FETAL PULSE OXIMETRY: RECOMMENDATION 10: ST WAVEFORM ANALYSIS: RECOMMENDATION 11: INTRAPARTUM FETAL SCALP LACTATE TESTING.

Significant reduction in umbilical artery metabolic acidosis after implementation of intrapartum ST waveform analysis of the fetal electrocardiogram

BACKGROUND

Although the evidence regarding the benefit of using ST waveform analysis of the fetal electrocardiogram is conflicting, ST waveform analysis is considered as adjunct to identify fetuses at risk for asphyxia in our center. Most randomized controlled trials and meta-analyses have not shown a significant decrease in umbilical metabolic acidosis, while some observational studies have shown a gradual decrease of this outcome over a longer period of time. Observational studies can give more insight into the effect of implementation of the ST technology in daily clinical practice.

OBJECTIVE

To evaluate the change in frequency of perinatal intervention and adverse neonatal outcome after the implementation of ST waveform analysis of the fetal electrocardiogram from 2000 to 2013.

STUDY DESIGN

This retrospective longitudinal study was conducted in a tertiary referral center. A total of 19,664 medium- and high-risk singleton pregnancies with fetuses in cephalic presentation, a gestational age of ≥36 weeks, and the intention to deliver vaginally were included. ST waveform analysis of the fetal electrocardiogram was implemented in the year 2000 and by 2010 all deliveries were monitored using this technology. Data were collected on the following perinatal outcomes: fetal blood sampling, mode of delivery, umbilical cord blood gases, Apgar scores, neonatal encephalopathy, and perinatal death. Longitudinal trend analysis was used to detect changes over time in all deliveries monitored by cardiotocography either alone or in adjunct to ST waveform analysis of the fetal electrocardiogram. Logistic regression was used to correct for possible confounders.

RESULTS

The umbilical artery metabolic acidosis rate declined from 2.5% (average rate of 2000 + 2001 + 2002) to 0.4% (average of 2011 + 2012 + 2013) (P < .001), which represents an 84% decrease. This decrease largely occurred between 2006 and 2008, during the Dutch randomized trial on fetal electrocardiogram ST waveform analysis. At this time, approximately 20% of deliveries were monitored using this method. Furthermore, there were significant reductions in fetal blood sampling rate (P < .001). Overall cesarean and vaginal instrumental deliveries decreased significantly (P < .001), but not for fetal distress. There were no changes in the Apgar scores. The incidence of neonatal encephalopathy was significantly lower in the second part of the study (odds ratio 0.39, 95% confidence interval 0.17-0.89).

CONCLUSION

There was an 84% decrease in the incidence of umbilical artery metabolic acidosis in all deliveries between 2000 and 2013. The neonatal encephalopathy rate, fetal blood sampling rate, and the total number of cesarean and vaginal instrumental deliveries also decreased.

Home-based mobile fetal/maternal electrocardiogram acquisition and extraction with cloud assistance

Electrocardiogram (ECG) monitoring of the fetus during pregnancy, before and during labor, can provide crucial information for the assessment of fetal well-being and development, as well as labor progress. An out-of-clinics fetal ECG monitoring system may pave the way for instant diagnosis, suggesting immediate intervention, which could help reduce the fetal mortality rate. In this paper, we present an unobtrusive fetal maternal ECG monitoring system which can operate in the home setting. The acquisition of the mother's abdominal ECG is done using the non-contact electrode approach. The extraction of the fetal ECG from the combined fetal/maternal ECG signal is investigated using both Fast Independent Component Analysis (FastICA) and RobustICA algorithms. An accelerometer is integrated for motion artifact detection which would help reduce interferences due to movement. The device also is connected to a cloud server, allowing doctors to access the data in real time.

Computerised interpretation of the fetal heart rate during labour: a randomised controlled trial (INFANT)

BACKGROUND

Continuous electronic fetal monitoring (EFM) in labour is widely used and computerised interpretation has the potential to increase its utility.

OBJECTIVES

This trial aimed to find out whether or not the addition of decision support software to assist in the interpretation of the cardiotocograph (CTG) reduced the number of poor neonatal outcomes, and whether or not it was cost-effective.

DESIGN

Two-arm individually randomised controlled trial. The allocations were computer generated using stratified block randomisation employing variable block sizes. The trial was not masked.

SETTING

Labour wards in England, Scotland and the Republic of Ireland.

PARTICIPANTS

Women in labour having EFM, with a singleton or twin pregnancy, at ≥ 35 weeks' gestation.

INTERVENTIONS

Decision support or no decision support.

MAIN OUTCOME MEASURES

The primary outcomes were (1) a composite of poor neonatal outcome {intrapartum stillbirth or early neonatal death (excluding lethal congenital anomalies), or neonatal morbidity [defined as neonatal encephalopathy (NNE)], or admission to a neonatal unit within 48 hours for ≥ 48 hours (with evidence of feeding difficulties, respiratory illness or NNE when there was evidence of compromise at birth)}; and (2) developmental assessment at the age of 2 years in a subset of surviving children.

RESULTS

Between 6 January 2010 and 31 August 2013, 47,062 women were randomised and 46,042 were included in the primary analysis (22,987 in the decision support group and 23,055 in the no decision support group). The short-term primary outcome event rate was higher than anticipated. There was no evidence of a difference in the incidence of poor neonatal outcome between the groups: 0.7% (n = 172) of babies in the decision support group compared with 0.7% (n = 171) of babies in the no decision support group [adjusted risk ratio 1.01, 95% confidence interval (CI) 0.82 to 1.25]. There was no evidence of a difference in the long-term primary outcome of the Parent Report of Children's Abilities-Revised with a mean score of 98.0 points [standard deviation (SD) 33.8 points] in the decision support group and 97.2 points (SD 33.4 points) in the no decision support group (mean difference 0.63 points, 95% CI -0.98 to 2.25 points). No evidence of a difference was found for health resource use and total costs. There was evidence that decision support did change practice (with increased fetal blood sampling and a lower rate of repeated alerts).

LIMITATIONS

Staff in the control group may learn from exposure to the decision support arm of the trial, resulting in improved outcomes in the control arm. This was identified in the planning stage and felt to be unlikely to have a significant effect on the results. As this was a pragmatic trial, the response to CTG alerts was left to the attending clinicians.

CONCLUSIONS

This trial does not support the hypothesis that the use of computerised interpretation of the CTG in women who have EFM in labour improves the clinical outcomes for mothers or babies.

FUTURE WORK

There continues to be an urgent need to improve knowledge and training about the appropriate response to CTG abnormalities, including timely intervention.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN98680152.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) HTA programme and will be published in full in Health Technology Assessment; Vol. 22, No. 9. See the NIHR Journals Library website for further project information. Sara Kenyon was part funded by the NIHR Collaboration for Leadership in Applied Health Research and Care West Midlands.

A Strategy for Classification of "Vaginal vs. Cesarean Section" Delivery: Bivariate Empirical Mode Decomposition of Cardiotocographic Recordings

We propose objective and robust measures for the purpose of classification of "vaginal vs. cesarean section" delivery by investigating temporal dynamics and complex interactions between fetal heart rate (FHR) and maternal uterine contraction (UC) recordings from cardiotocographic (CTG) traces. Multivariate extension of empirical mode decomposition (EMD) yields intrinsic scales embedded in UC-FHR recordings while also retaining inter-channel (UC-FHR) coupling at multiple scales. The mode alignment property of EMD results in the matched signal decomposition, in terms of frequency content, which paves the way for the selection of robust and objective time-frequency features for the problem at hand. Specifically, instantaneous amplitude and instantaneous frequency of multivariate intrinsic mode functions are utilized to construct a class of features which capture nonlinear and nonstationary interactions from UC-FHR recordings. The proposed features are fed to a variety of modern machine learning classifiers (decision tree, support vector machine, AdaBoost) to delineate vaginal and cesarean dynamics. We evaluate the performance of different classifiers on a real world dataset by investigating the following classifying measures: sensitivity, specificity, area under the ROC curve (AUC) and mean squared error (MSE). It is observed that under the application of all proposed 40 features AdaBoost classifier provides the best accuracy of 91.8% sensitivity, 95.5% specificity, 98% AUC, and 5% MSE. To conclude, the utilization of all proposed time-frequency features as input to machine learning classifiers can benefit clinical obstetric practitioners through a robust and automatic approach for the classification of fetus dynamics.

Fetal Heart Rate Auscultation, 3rd edition

The use of intermittent auscultation (IA) for fetal surveillance during labor decreased with the introduction of electronic fetal monitoring (EFM). The increased use of EFM is associated with an increase in cesarean births. IA is an evidence-based method of fetal surveillance during labor for women with low risk pregnancies and considered one component of comprehensive efforts to reduce the primary cesarean rate and promote vaginal birth. Many clinicians are not familiar with IA practice. This practice monograph includes information on IA techniques; interpretation and documentation; clinical decision-making and interventions; communication; education, staffing, legal issues, and strategies to promote implementation of IA into practice.

Cardiotocography alone vs. cardiotocography with ST segment analysis for intrapartum fetal monitoring in women with late-term pregnancy. A randomized controlled trial

OBJECTIVES

Randomized studies have obtained conflicting results regarding the usefulness of fetal electrocardiographic (ECG) ST-segment analysis, possibly because these studies included non-homogeneous populations. We designed a study to determine whether this monitoring technique is potentially useful for populations at risk for fetal heart rate alterations during labor, i.e. groups of women who share late-term pregnancy as a risk factor.

STUDY DESIGN

This randomized clinical trial recruited women whose pregnancy had lasted more than 290 days. The participants were randomly assigned to continuous fetal cardiotocographic monitoring alone (CTG group) or with fetal ECG ST-segment analysis (ECG-F group). In the CTG group fetal heart rate was interpreted according to guidelines from the National Institute of Child Health and Human Development, whereas in the ECG-F group the tracings were interpreted according the original International Federation of Gynecology and Obstetrics (FIGO) guidelines. The primary outcome measure was neonatal outcome, evaluated as arterial blood pH in neonates after abdominal or vaginal operative delivery indicated because of nonreassuring fetal status.

RESULTS

A total of 237 women were randomized, of whom 200 were included in the final analysis (100 in each group). The rate of cesarean delivery was the same in both groups (26%), and the rate of operative delivery due to nonreassuring fetal status did not differ significantly (38% in the CTG group vs. 39% in the ECG-F group). Regarding neonatal outcomes, there was no significant difference between groups in neonatal pH (7.27 [7.23-7.29] and 7.25 [7.21-7.27]).

CONCLUSIONS

In a population comprising only late-term pregnancies, fetal ECG monitoring had no benefits for the mother or fetus. Additional studies are needed of protocols for using ST waveform analysis in selected population groups.

Computerised analysis of intrapartum fetal heart rate patterns and adverse outcomes in the INFANT trial

OBJECTIVE

To assess if a computerised decision support system reliably identified abnormal fetal heart rate (FHR) patterns in fetuses with adverse neonatal outcomes in the INFANT trial, and whether its use reduced substandard care.

DESIGN

Prospective cohort study within a randomised controlled trial.

SETTING

Twenty-four maternity units in the UK and Ireland.

POPULATION OR SAMPLE

A total of 46 614 labours between January 6 2010 and August 31 2013 in the INFANT trial.

METHODS

Panel review of intrapartum and neonatal care in infants with adverse outcome, and an assessment of the effectiveness of computerised interpretation of fetal heart rate in reducing substandard care. Descriptive analysis of other factors associated with adverse outcome.

MAIN OUTCOME MEASURES

Incidence and detection rate of abnormal fetal heart rate patterns, other characteristics associated with perinatal adverse outcome, and frequency of substandard care.

RESULTS

Computer interpretation of FHR patterns was deemed to be completely valid in only 24 of 71 (33.8%) cases of adverse outcome. On a scale of 0-10 (completely invalid to completely valid), 28 cases (39.4%) had a score of 6 or less, mainly due to lack of recognition of decelerations (15 cases), or reduced variability (seven cases), or failure to recognise tachysystole (five cases). There were multiple associated factors that modified the clinical assessment of FHR patterns. There was substandard care in 45/71 cases (63%).

CONCLUSION

A significant proportion of abnormal fetal heart rate patterns were not detected accurately by computer analysis, and its use did not reduce the incidence of substandard care.

FUNDING

UK National Institute for Health Research Health Technology Assessment Programme (project number 06.38.01).

TWEETABLE ABSTRACT

Improved recognition of abnormal fetal heart rate patterns is insufficient to reduce the incidence of substandard care.

Update on Fetal Monitoring: Overview of Approaches and Management of Category II Tracings

Electronic fetal monitoring (EFM) is widely used to assess fetal status in labor. Use of intrapartum continuous EFM is associated with a lower risk of neonatal seizures but a higher risk of cesarean or operative delivery. Category II fetal heart tracings (FHTs) are indeterminate in their ability to predict fetal acidemia. Certain patterns of decelerations and variability within this category may be predictive of neonatal morbidity. Adjunct tests of fetal well-being can be used during labor to further triage patients. Intrauterine resuscitation techniques should target the suspected etiology of intrapartum fetal hypoxia. Clinical factors play a role in the interpretation of EFM.

The importance of the learning process in ST analysis interpretation and its impact in improving clinical and neonatal outcomes

BACKGROUND

Intrapartum fetal heart rate monitoring was introduced with the goal to reduce fetal hypoxia and deaths. However, continuous fetal heart rate monitoring has been shown to have a high sensitivity but also a high false-positive rate. To improve specificity, adjunctive technologies have been developed to identify fetuses at risk for intrapartum asphyxia. Intensive research on the value of ST-segment analysis of the fetal electrocardiogram as an adjunct to standard electronic fetal monitoring in lowering the rates of fetal metabolic acidosis and operative deliveries has been ongoing. The conflicting results in randomized and observational studies may partly be due to differences in study design.

OBJECTIVE

This study aims to determine the significance of the learning process for the introduction of ST analysis into clinical practice and its impact on initial and subsequent obstetric outcomes.

STUDY DESIGN

This was a prospective observational study with the primary objective to evaluate the importance of the learning period on the rates of metabolic acidosis and operative deliveries after the implementation of ST analysis. The study was conducted at the Turku University Hospital, Turku, Finland, with 3400-4200 annual deliveries. The whole study population consisted of all 42,146 deliveries during the study period 2001 through 2011. The ST analysis usage rate was 18%. The data were collected prospectively from labors monitored with ST analysis as an adjunct to conventional intrapartum fetal heart rate monitoring. Primary endpoints were the rates of metabolic acidosis (cord artery pH <7.05 and an extracellular fluid compartment base deficit >12.0 mmol/L), fetal scalp blood sampling, and operative deliveries. Comparisons of these outcomes were made between the initiation period (the first 2 years) and the subsequent usage period (the next 9 years).

RESULTS

In the whole study population the prevalence of cord pH <7.05 decreased from 1.5-0.81% (relative risk, 0.54; 95% confidence interval, 0.43-0.67), the rate of cesarean deliveries from 17.2-14.1% (relative risk, 0.82; 95% confidence interval, 0.89-0.97), and the rate of fetal scalp blood sampling from 1.75-0.82% (relative risk, 0.47; 95% confidence interval, 0.38-0.58) when the 2 study periods were compared. In the ST analysis group, the frequency of cord metabolic acidosis rate was reduced from 1.0-0.25% (relative risk, 0.33; 95% confidence interval, 0.15-0.72).

CONCLUSION

We provide evidence that the results improve over time and there is a learning curve in the introduction of the ST analysis method. This was demonstrated by the lower rates of metabolic acidosis and operative deliveries after the initial implementation period.

Comparative Effectiveness of ICA and PCA in Extraction of Fetal ECG From Abdominal Signals: Toward Non-invasive Fetal Monitoring

Non-adaptive signal processing methods have been successfully applied to extract fetal electrocardiograms (fECGs) from maternal abdominal electrocardiograms (aECGs); and initial tests to evaluate the efficacy of these methods have been carried out by using synthetic data. Nevertheless, performance evaluation of such methods using real data is a much more challenging task and has neither been fully undertaken nor reported in the literature. Therefore, in this investigation, we aimed to compare the effectiveness of two popular non-adaptive methods (the ICA and PCA) to explore the non-invasive (NI) extraction (separation) of fECGs, also known as NI-fECGs from aECGs. The performance of these well-known methods was enhanced by an adaptive algorithm, compensating amplitude difference and time shift between the estimated components. We used real signals compiled in 12 recordings (real01-real12). Five of the recordings were from the publicly available database (PhysioNet-Abdominal and Direct Fetal Electrocardiogram Database), which included data recorded by multiple abdominal electrodes. Seven more recordings were acquired by measurements performed at the Institute of Medical Technology and Equipment, Zabrze, Poland. Therefore, in total we used 60 min of data (i.e., around 88,000 R waves) for our experiments. This dataset covers different gestational ages, fetal positions, fetal positions, maternal body mass indices (BMI), etc. Such a unique heterogeneous dataset of sufficient length combining continuous Fetal Scalp Electrode (FSE) acquired and abdominal ECG recordings allows for robust testing of the applied ICA and PCA methods. The performance of these signal separation methods was then comprehensively evaluated by comparing the fetal Heart Rate (fHR) values determined from the extracted fECGs with those calculated from the fECG signals recorded directly by means of a reference FSE. Additionally, we tested the possibility of non-invasive ST analysis (NI-STAN) by determining the T/QRS ratio. Our results demonstrated that even though these advanced signal processing methods are suitable for the non-invasive estimation and monitoring of the fHR information from maternal aECG signals, their utility for further morphological analysis of the extracted fECG signals remains questionable and warrants further work.

Relationship Between Short Term Variability (STV) and Onset of Cerebral Hemorrhage at Ischemia-Reperfusion Load in Fetal Growth Restricted (FGR) Mice

Fetal growth restriction (FGR) is a risk factor exacerbating a poor neurological prognosis at birth. A disease exacerbating a poor neurological prognosis is cerebral palsy. One of the cause of this disease is cerebral hemorrhage including intraventricular hemorrhage. It is believed to be caused by an inability to autoregulate cerebral blood flow as well as immaturity of cerebral vessels. Therefore, if we can evaluate the function of autonomic nerve, cerebral hemorrhage risk can be predicted beforehand and appropriate delivery management may be possible. Here dysfunction of autonomic nerve in mouse FGR fetuses was evaluated and the relationship with cerebral hemorrhage incidence when applying hypoxic load to resemble the brain condition at the time of delivery was examined. Furthermore, FGR incidence on cerebral nerve development and differentiation was examined at the gene expression level. FGR model fetuses were prepared by ligating uterine arteries to reduce placental blood flow. To compare autonomic nerve function in FGR mice with that in control mice, fetal short term variability (STV) was measured from electrocardiograms. In the FGR group, a significant decrease in the STV was observed and dysfunction of cardiac autonomic control was confirmed. Among genes related to nerve development and differentiation, Ntrk and Neuregulin 1, which are necessary for neural differentiation and plasticity, were expressed at reduced levels in FGR fetuses. Under normal conditions, Neurogenin 1 and Neurogenin 2 are expressed mid-embryogenesis and are related to neural differentiation, but they are not expressed during late embryonic development. The expression of these two genes increased in FGR fetuses, suggesting that neural differentiation is delayed with FGR. Uterine and ovarian arteries were clipped and periodically opened to give a hypoxic load mimicking the time of labor, and the bleeding rate significantly increased in the FGR group. This suggests that FGR deteriorates cardiac autonomic control, which becomes a risk factor for cerebral hemorrhage onset at birth. This study demonstrated that cerebral hemorrhage risk may be evaluated before parturition for FGR management by evaluating the STV. Further, this study suggests that choosing an appropriate delivery timing and delivery method contributes to neurological prognosis improvement.

[Stained amniotic fluid and meconium amniotic fluid: Should they change our obstetric management ?]

OBJECTIVES

To assess if a stained or meconial amniotic fluid during labor is correlated with a greater risk of neonatal metabolic acidosis.

METHODS

In a retrospective case-control study carried out in a level 3 maternity from 1st of January to 31st of December 2014, all patients who delivered a singleton eutrophic fetus in cephalic presentation after 37WG and with a stained or meconial amniotic fluid during labor were included. Obstetrical and neonatal outcomes were compared according to the amniotic fluid's color.

RESULTS

At all, 302 patients in the group « Abnormal amniotic fluid» (198 patients with stained amniotic fluid, 104 with meconial amniotic fluid) vs. 302 in the group « clear amniotic fluid» were included. No significant difference on the rate of neonatal severe acidosis between the two groups were found. Fetal heart rhythm abnormalities were more frequent in case of meconial amniotic fluid (11,3% vs. 31,7%, P<0,0001). The composite endpoint, defined by the association of umbilical arterial pH <7,0±base excess ≥12mmol/L±Apgar score at 5min <7, was more frequent in case of meconial amniotic fluid (4,0% vs. 12,5%, P=0,0018).

CONCLUSION

The occurrence of severe neonatal metabolic acidosis was not more frequent in case of stained or meconial amniotic fluid, but with an increase in the use of fetal scalp pH and cesaerian deliveries when the fluid was meconial.

First do the experiment: Do computerised interpretation of cardiotocography and other widely used interventions improve newborn outcomes?

The introduction of continuous electronic fetal heart rate monitoring (EFM) in labour has coincided with a steady and remarkable fall in perinatal mortality. Whether this is cause or coincidence remains unclear because randomised trials have been underpowered. Attempts to improve the sensitivity and specificity of fetal compromise detection using fetal blood sampling and pH measurement, pulse oximetry, and fetal electrocardiogram analysis have failed to provide evidence of additional value in randomised trials. Recently, litigation to obtain compensation for obstetric and midwifery error, often reported to be failure to recognise abnormal EFM traces, has escalated. The hypothesis that computerised heart rate pattern recognition could reduce adverse outcomes was tested in a randomised controlled trial of 46,000 labours but showed no benefit. It seems that complicating risk factors such as fetal growth restriction, meconium liquor, pyrexia in labour, and excessive use of oxytocin, are more important than previously realised.

Agreement of three interpretation systems of intrapartum foetal heart rate monitoring by different levels of physicians

A prospective study was conducted in centre in Southern Thailand, to evaluate agreement in EFM interpretation among various physicians in order to find out the most practical system for daily use. We found strong agreement of very normal FHR tracings among the FIGO, NICHD 3-tier and 5-tier systems. The NICHD 3-tier was more compatible with the FIGO system than 5-tier system. Overall inter-observer agreement was moderate for the NICHD 3-tier system while inter-observer agreement of 5-tier system was fair also the intra-observer agreement was higher in the NICHD 3-tier system. So the 3-tier systems are more suitable than the 5-tier system in general obstetric practice. Impact statement What is already known on this subject: The 3-tier and 5-tier systems were widely used in general obstetrics practice. What the results of this study add: The inter- and intra-observer agreement of NICHD 3-tier system was higher than the 5-tier system. What the implications are of these findings for clinical practice and/or further research: The 3-tier systems were more suitable than the 5-tier systems in general obstetrics practice.

Criteria-based audit to improve quality of care of foetal distress: standardising obstetric care at a national referral hospital in a low resource setting, Tanzania

BACKGROUND

In Tanzania, substandard intrapartum management of foetal distress contributes to a third of perinatal deaths, and the majority are term deliveries. We conducted a criteria-based audit with feedback to determine whether standards of diagnosis and management of foetal distress would be improved in a low-resource setting.

METHODS

During 2013-2015, a criteria-based audit was performed at the national referral hospital in Dar es Salaam. Case files of deliveries with a diagnosis of foetal distress were identified and audited. Two registered nurses under supervision of a nurse midwife, a specialist obstetrician and a consultant obstetrician, reviewed the case files. Criteria for standard diagnosis and management of foetal distress were developed based on international and national guidelines, and literature reviews, and then, stepwise applied, in an audit cycle. During the baseline audit, substandard care was identified, and recommendations for improvement of care were proposed and implemented. The effect of the implementations was assessed by the differences in percentage of standard diagnosis and management between the baseline and re-audit, using Chi-square test or Fisher's exact test, when appropriate.

RESULTS

In the baseline audit and re-audit, 248 and 251 deliveries with a diagnosis of foetal distress were identified and audited, respectively. The standard of diagnosis increased significantly from 52 to 68 % (p < 0.001). Standards of management improved tenfold from 0.8 to 8.8 % (p < 0.001). Improved foetal heartbeat monitoring using a Fetal Doppler was the major improvement in diagnoses, while change of position of the mother and reduced time interval from decision to perform caesarean section to delivery were the major improvements in management (all p < 0.001). Percentage of cases with substandard diagnosis and management was significantly reduced in both referred public and non-referred private patients (all p ≤ 0.01) but not in non-referred public and referred private patients.

CONCLUSION

The criteria-based audit was able to detect substandard diagnosis and management of foetal distress and improved care using feedback and available resources.

Cardiotocography in breech versus vertex delivery: an examiner-blinded, cross-sectional nested case-control study

BACKGROUND

The safety of vaginal breech delivery has been debated for decades. Although it has been shown to predispose infants to immediate depression, several observational studies have also shown that attempting vaginal breech delivery does not increase perinatal morbidity or low Apgar score at the age of five minutes. Cardiotocography monitoring is recommended during vaginal breech delivery, but comparative data describing differences between cardiotocography tracings in breech and vertex deliveries is scarce. This study aims to evaluate differences in intrapartum cardiotocography tracings between breech and vertex deliveries in the final 60 min of delivery. A secondary goal is to identify risk factors for suboptimal neonatal outcome in the study population.

METHODS

One hundred eight breech and 108 vertex singleton, intended vaginal deliveries at term from a tertiary hospital with 5000 annual deliveries were included. Two experienced obstetricians, blinded to fetal presentation, neonatal outcome and actual mode of delivery, evaluated traces recorded 60 min before delivery. They provided a three-tier classification and evaluated different trace features according to FIGO (1987) guidelines. Factors associated with acidemia and low Apgar scores were identified by univariate and multivariable analyses performed with binary logistic regression. Student's T-test and chi-square test were used, as appropriate.

RESULTS

Late decelerations were seen in 13.9 % of breech and 2.8 % of vertex deliveries (p = 0.003) and decreased variability in 26.9 % of breech and 8.3 % of vertex deliveries (p < 0.001). In multivariable analysis complicated variable decelerations and breech presentation were identified as risk factors for neonatal acidemia and low Apgar score at the age of five minutes. Pathological trace and breech presentation were independent risk factors for low Apgar score at the age of one minute.

CONCLUSIONS

Decreased variability and late decelerations were more prevalent in breech compared to vertex deliveries. Pathological trace predicts immediate neonatal depression and especially complicated variable decelerations may signal more severe distress. Further research is needed to create guidelines for safe management of vaginal breech delivery.

Fetal heart rate monitoring of short term variation (STV): a methodological observational study

BACKGROUND

Cardiotocography (CTG) has high sensitivity, but less specificity in detection of fetal hypoxia. There is need for adjunctive methods easy to apply during labor. Low fetal heart rate short term variation (STV) is predictive for hypoxia during the antenatal period. The objectives of our study were to methodologically evaluate monitoring of STV during labor and to compare two different monitors (Sonicaid™ and EDAN™) for antenatal use.

METHODS

A prospective observational study at the obstetric department, Karolinska University hospital, Stockholm (between September 2011 and April 2015). In 100 women of ≥ 36 weeks gestation, STV values were calculated during active labor. In a subset of 20 women we compared STV values between internal and external signal acquisition. Additionally we compared antenatal monitoring with two different monitors in another 20 women.

RESULTS

Median STV in 100 fetuses monitored with scalp electrode during labor (EDAN™) was 7.1 msec (range 1.3-25.9) with no difference between early (3-6 cm) and late (7-10 cm) labor (7.1 vs 6.8 msec; p = 0.80). STV calculated from scalp electrode signals were positively correlated with delta-STV (STV internal -external) (R = 0.70; p < 0.01). No significant differences were found between Sonicaid™ and EDAN™ in antenatal external monitoring of STV (median difference 0.9 msec, Spearman Rank Correlation Sonicaid vs delta-STV; R = 0.35; p = 0.14).

CONCLUSIONS

Median intrapartum STV was 7.1 msec. Significant differences were found between internal and external signal acquisition, a finding that suggests further intrapartum studies to be analysed separately depending upon type of signal acquisition. Antenatal external monitoring with Sonicaid™ and EDAN™ indicates that the devices perform equally well in the identification of acidemic fetuses. Further studies are needed to assess the clinical value of intrapartum STV.

A study of an intelligent system to support decision making in the management of labour using the cardiotocograph - the INFANT study protocol

BACKGROUND

Continuous electronic fetal heart rate monitoring in labour is widely used but its potential for improving fetal and neonatal outcomes has not been realised. The most likely reason is the difficulty of interpreting the fetal heart rate trace correctly during labour. Computerised interpretation of the fetal heart rate and intelligent decision-support has the potential to deliver this improvement in care. This trial will test whether the addition of decision support software to aid the interpretation of the cardiotocogram (CTG) during labour will reduce the number of 'poor neonatal outcomes' in those women judged to require continuous electronic fetal heart rate monitoring.

METHODS AND DESIGN

An individually randomised controlled trial of 46,000 women who are judged to require continuous electronic fetal monitoring in labour.

ELIGIBILITY CRITERIA

Women admitted to a participating labour ward who are judged to require continuous electronic fetal monitoring, have a singleton or twin pregnancy, are ≥ 35 weeks' gestation, have no known gross fetal abnormality and are ≥ 16 years of age.

EXCLUSION CRITERIA

Triplets or higher order pregnancy, elective caesarean section prior to the onset of labour, planned admission to NICU. Trial interventions: Computerised interpretation of the CTG with decision-support.

PRIMARY OUTCOMES

Short term: A composite of 'poor neonatal outcome' including stillbirth after trial entry, early neonatal death except deaths due to congenital anomalies, significant morbidity: neonatal encephalopathy, admissions to the neonatal unit with 48 h for > 48 h with evidence of feeding difficulties, respiratory illness or encephalopathy where there is evidence of compromise at birth. Long term: Developmental assessment at the age of 2 years in a subset of 7000 surviving babies.

DATA COLLECTION

For all participating women and babies, labour variables and outcomes will be stored automatically and contemporaneously onto the Guardian® system.

DISCUSSION

The results of this trial will have importance for pregnant women and for health professionals who provide care for them.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN98680152 assigned 30.09.2008.

An Exploration of the Views and Experiences of Midwives Using Intermittent Auscultation of the Fetal Heart in Labor

OBJECTIVES: To identify the experiences of midwives using intermittent auscultation of the fetal heart rate in labor.

DESIGN: A qualitative descriptive study with a sample of 8 midwives, 3 from a DOMINO scheme and 5 from the labor ward at an Irish urban maternity unit. Data collection was through tape-recorded semistructured interviews. Data analysis involved transcription of the interviews verbatim and thematic analysis.

FINDINGS: Three core themes were identified: vulnerability, the culture of the organization, and walking the tightrope. The findings suggest that the main challenges which inhibit midwives using intermittent auscultation is the lack of professional guidelines, inconsistency in documentation, and working in a biomedical model of care. The participants also identified that midwives practicing in a midwifery social model of care have more confidence and use midwifery skills to support the use of intermittent auscultation.

CONCLUSIONS: The findings suggest working within a midwifery social model of care facilitates the use of intermittent auscultation. Guidelines and education on the explicit use of intermittent auscultation need to be made accessible to midwives. Midwives believed that women could promote the use of intermittent auscultation through their own education on monitoring fetal heart rate options in labor.

A Low-Voltage Chopper-Stabilized Amplifier for Fetal ECG Monitoring With a 1.41 Power Efficiency Factor

This paper presents a low-voltage current-reuse chopper-stabilized frontend amplifier for fetal ECG monitoring. The proposed amplifier allows for individual tuning of the noise in each measurement channel, minimizing the total power consumption while satisfying all application requirements. The low-voltage current reuse topology exploits power optimization in both the current and the voltage domain, exploiting multiple supply voltages (0.3, 0.6 and 1.2 V). The power management circuitry providing the different supplies is optimized for high efficiency (peak charge-pump efficiency = 90%).The low-voltage amplifier together with its power management circuitry is implemented in a standard 0.18 μm CMOS process and characterized experimentally. The amplifier core achieves both good noise efficiency factor (NEF=1.74) and power efficiency factor (PEF=1.05). Experiments show that the amplifier core can provide a noise level of 0.34 μVrms in a 0.7 to 182 Hz band, consuming 1.17 μW power. The amplifier together with its power management circuitry consumes 1.56 μW, achieving a PEF of 1.41. The amplifier is also validated with adult ECG and pre-recorded fetal ECG measurements.

Are we (mis)guided by current guidelines on intrapartum fetal heart rate monitoring? Case for a more physiological approach to interpretation

Original interpretations of fetal heart rate (FHR) patterns equated FHR decelerations with 'fetal distress', requiring expeditious delivery. This simplistic interpretation is still implied in our clinical guidelines despite 40 years of increasing understanding of the behaviour and regulation of the fetal cardiovascular system during labour. The physiological basis of FHR responses and adaptations to oxygen deprivation is de-emphasised, whilst generations of obstetricians and midwives are trained to focus on, and classify, the morphological appearances of decelerations into descriptive categories, with no attempt to understand how the fetus defends itself and compensates for intrapartum hypoxic ischaemic insults, or the patterns that suggest progressive loss of compensation. Consequently, there is a lack of confidence, marked variation in FHR interpretation, defensive practices, unnecessary operative interventions, and a failure to recognise abnormal FHR patterns, resulting in adverse outcomes and expensive litigation.

Interrelations between four antepartum obstetric interventions and cesarean delivery in women at low risk: a systematic review and modeling of the cascade of interventions

OBJECTIVES

To critically appraise the literature on the relations between four intrapartum obstetric interventions-electronic fetal monitoring (EFM), epidural analgesia, labor induction, and labor acceleration; and two types of delivery-instrumental (forceps and vacuum) and cesarean section.

METHODS

This review included meta-analyses published between January 2000 and April 2012 including at least one randomized clinical trial published after 1995 and presenting results on low-risk pregnancies between 37 and 42 weeks of gestation, searched in the databases Medline, Cochrane Library, and EMBASE with no language restriction.

RESULTS

Of 306 documents identified, 8 fulfilled the inclusion criteria and presented results on women at low risk. EFM at admission (vs intermittent auscultation) was associated with cesarean delivery (odds ratio [OR] = 1.20, 95% confidence interval [CI] 1.00-1.44) and epidural analgesia (OR = 1.25, 95% CI 1.09-1.43). Epidural on request was associated with cesarean delivery (OR = 1.60, 95% CI 1.18-2.18), instrumental delivery (OR = 1.21, 95% CI 1.03-1.44), and oxytocin use (OR = 1.20, 95% CI 1.01-1.43) when compared with epidural on request plus nonpharmacological labor pain control methods such as one-to-one support, breathing techniques, and relaxation. Induction and acceleration of labor showed heterogeneous patterns of associations with cesarean delivery and instrumental delivery.

CONCLUSIONS

Complex patterns of associations between obstetric interventions and modes of delivery were illustrated in an empirical model. Intermittent auscultation and nonpharmacological labor pain control interventions, such as one-to-one support during labor, have the potential for substantially reducing cesarean deliveries.

What is the "normal" fetal heart rate?

Aim. There is no consensus about the normal fetal heart rate. Current international guidelines recommend for the normal fetal heart rate (FHR) baseline different ranges of 110 to 150 beats per minute (bpm) or 110 to 160 bpm. We started with a precise definition of "normality" and performed a retrospective computerized analysis of electronically recorded FHR tracings. Methods. We analyzed all recorded cardiotocography tracings of singleton pregnancies in three German medical centers from 2000 to 2007 and identified 78,852 tracings of sufficient quality. For each tracing, the baseline FHR was extracted by eliminating accelerations/decelerations and averaging based on the "delayed moving windows" algorithm. After analyzing 40% of the dataset as "training set" from one hospital generating a hypothetical normal baseline range, evaluation of external validity on the other 60% of the data was performed using data from later years in the same hospital and externally using data from the two other hospitals. Results. Based on the training data set, the "best" FHR range was 115 or 120 to 160 bpm. Validation in all three data sets identified 120 to 160 bpm as the correct symmetric "normal range". FHR decreases slightly during gestation. Conclusions. Normal ranges for FHR are 120 to 160 bpm. Many international guidelines define ranges of 110 to 160 bpm which seem to be safe in daily practice. However, further studies should confirm that such asymmetric alarm limits are safe, with a particular focus on the lower bound, and should give insights about how to show and further improve the usefulness of the widely used practice of CTG monitoring.