Knowledge of adverse neonatal outcome alters clinicians’ interpretation of the intrapartum cardiotocograph

Labor management and neonatal outcomes in cardiotocography categories II and III (Review)

The safe care of both mothers and fetuses during labor is a primary goal of all health professionals. The assessment of fetal oxygenation and well-being is a key aspect of perinatal care provided. Fetal heart rate (FHR) auscultation became part of daily obstetric practice in a number of countries during the 20th century and remains a key method of fetal monitoring, particularly in low-risk pregnancies. Cardiotocography (CTG) is the continuous monitoring and recording of the FHR and uterine myometrial activity, making it possible to assess the fetal condition. It therefore plays a critical role in the detection of fetal hypoxia during labor, a condition directly related to short- and long-term complications in the newborn. Herein, particular reference is made to the management of CTG category II and III standards, as well as to the handling of childbirth. In addition, specific FHR patterns are associated with immediate neonatal outcomes based on updated studies conducted worldwide. Finally, the prognostic significance of CTG and its potential as a prospective avenue for further investigation are also highlighted herein. Given that the misinterpretation of CTG findings is the most common cause of medical-legal responsibility, this knowledge field requires more emphasis and attention. The aim of the present review was to further deepen the knowledge on issues that mainly concern the safety and monitoring of pregnant women and fetuses during childbirth.

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.

CTG interpretation templates affect residents' decision making

OBJECTIVE

To study whether a revision of CTG guidelines and educational program influenced the perceived need for intervention by residents in obstetrics and gynecology. A secondary aim was to study the sensitivity and specificity of the classification pathological after classification by residents using two different guidelines in identifying neonates with acidemia.

STUDY DESIGN

Cardiotocograms, CTGs, from 223 neonates with acidemia at birth (cord blood pH < 7.05 at vaginal birth or second stage cesarean, or pH < 7.10 at first stage cesarean) were included, as well as 223 CTGs from neonates with cord blood pH ≥ 7.15. Two separate groups of residents, who each were educated in and had clinical experience only from either of the two different guidelines, SWE09 and SWE17, classified the patterns according to the at the time current template and judged whether the patterns indicated an intervention. Sensitivity, specificity, and agreement were calculated.

RESULTS

Residents using SWE09 found indication to intervene in a higher proportion of neonates with acidemia (84.8%) than residents using SWE17 (75.8%; p = 0.002), as well as in cases without acidemia (29.6% vs 22.4%; p = 0.038). Among residents using SWE09 the perceived need for intervention had a sensitivity of 85% and a specificity of 70% to identify acidemia. With SWE17 the corresponding rates were 76% and 78%. The sensitivity to identify neonates with acidemia by classification pathological was 91% with SWE09 and 72% with SWE17. The specificity was 53% and 76% respectively. The agreement rate between perception of indication to intervene and classification pathological using the SWE09 was κ 0.73, moderate, and with the SWE17 κ 0.77, moderate. The agreement on subjective perception of necessity to intervene between users of the two templates was weak to moderate, κ 0.60, and on classification pathological weak, κ 0.47.

CONCLUSION

The perceived need for intervention by residents interpreting CTGs was significantly affected by the guidelines in use. The difference in decisions were less pronounced than the difference in classification. The sensitivity for both perceived need for intervention and for classification pathological to identify acidosis was higher with SWE09, and the specificity higher with SWE17, when assessed by the two comparable groups of residents.

Hazard and cumulative incidence of umbilical cord metabolic acidemia at birth in fetuses experiencing the second stage of labor and pathologic intrapartum fetal heart rate requiring expedited delivery

PURPOSE

The aim of the study was to determine the cause-specific hazard (CSH) and the cumulative incidence function (CIF) for umbilical cord metabolic acidemia at birth (MA; pH < 7.0 and/or BE [Formula: see text] - 12 mmol/L) at delivery in patients experiencing the 2nd stage of labor (2STG), stratified for both FIGO-2015 pathologic intrapartum cardiotocography requiring expedited delivery (CTG_RED) and duration of 2nd stage of labor.

METHODS

3459 pregnancies experiencing the 2nd stage of labor and delivering at the Division of Obstetrics and Prenatal Medicine, IRCCS Sant'Orsola-Malpighi Hospital, Bologna (Italy), were identified between 2018 and 2019. Survival analysis was used to assess CSH and CIF for MA, stratified for FIGO-2015 pathologic CTG and relevant covariates.

RESULTS

FIGO-2015 pathological CTG with expedited operative delivery or urgent cesarean section within 10 or 20 min from diagnosis, respectively occurred in 282/3459 (8.20%). The rate of MA at delivery was 3.32% (115/3459). The spline of CSH for MA showed a direct correlation with the duration of 2STG always presenting higher values and greater slope in the presence of pathologic CTG, with plateau between 60 and 120 min and rapid increase after 120 min. The CIF at 180 min in the 2STG was 2.67% for nonpathological and 10.63% for pathological CTG_RED. Nulliparity, pathological CTG, and meconium-stained amniotic fluid resulted significant predictors of MA in our multivariable model.

CONCLUSION

The risk for MA increases moderately across the 2STG with nonpathological CTG and quadruples with pathological CTG_RED. Adjustment for other predictors of MA including meconium-stained amniotic fluid and nulliparity reveals a significant hazard increase for MA associated with pathologic CTG_RED.

Types of intrapartum hypoxia in the newborn at term with metabolic acidemia: A retrospective study

INTRODUCTION

In the most recent recommendations of the International Federation of Gynecology and Obstetrics (FIGO), a chapter was dedicated to the physiological approach and to the description of fetal mechanisms developed to respond to hypoxia. Our objective was to classify the type of hypoxia in the case of metabolic acidemia and to describe the order of appearance of fetal heart rate abnormalities in cases of gradually evolving hypoxia.

MATERIAL AND METHODS

132 neonates born between 2018 and 2020 with acidemia were included. We excluded preterm birth, fetuses with congenital anomaly and twin pregnancies. Intrapartum cardiotocography traces were assigned to one of these four types of labor hypoxia: acute, subacute, gradually evolving and chronic hypoxia. For gradually evolving hypoxia, fetal heart rate abnormalities were described according to the FIGO classification.

RESULTS

36 cardiotocography traces (27.3%) were classified as acute hypoxia, 14 (10.6%) as subacute hypoxia, and 3 (3.2%) as chronic hypoxia; gradually evolving hypoxia occurred in 62 cases (47%). In 77.4% of cases of gradually evolving hypoxia, deceleration was the first anomaly to appear, with loss of variability and bradycardia appearing later. Increased fetal heart rate was observed immediately after late deceleration in 46.8% of cases and was followed by a loss of variability or saltatory rhythm in 37.1% of cases.

CONCLUSIONS

In cases of metabolic acidemia at term, the most frequent situation observed was gradually evolving hypoxia, with an initial occurrence of decelerations. The sequence of fetal heart rate modifications was variable.

The impact on obstetric and perinatal outcomes in term infants following the introduction of a colour-coded, hierarchical cardiotocography classification system: A retrospective non-inferiority study

BACKGROUND

Queensland introduced a colour-coded cardiotocograph (CTG) classification system (green, blue, yellow and red) to complement the Royal Australian and New Zealand College of Obstetricians and Gynaecologists prose-based classification system of 'low, unlikely, maybe or likely' fetal compromise.

AIMS

The aim of the study was to determine the clinical impact of the introduction of the colour-coded CTG classification system compared to the prose-based system. We hypothesised there would be no change in the rate of operative delivery for intrapartum fetal compromise (OD-IFC).

MATERIALS AND METHODS

This retrospective non-inferiority study from November 2014 to May 2018 used routinely collected data from the Mater Mother's Hospital. Non-insured women with a singleton, non-anomalous, cephalic fetus at term, attempting a vaginal birth with continuous intrapartum CTG were included. The primary outcome was OD-IFC. Secondary outcomes included various obstetric and perinatal outcomes. Non-inferiority analysis was performed with a pre-specified non-inferiority margin of 2% risk difference.

RESULTS

Eleven thousand seven hundred and twenty-seven participants were included. The OD-IFC rate was similar across the study groups (prose-based 15.1% vs colour-coded 15.3%, adjusted odds ratio (aOR) 1.02, 95% CI 0.93-1.13) with the adjusted risk difference of 0.29% (95% CI -0.98 to 1.56), which did not exceed the inferiority margin. There were more spontaneous (aOR 1.11, 95% CI 1.04-1.19) and fewer instrumental (aOR 0.87, 95% CI 0.80-0.95) vaginal births in the colour-coded cohort. There were no differences in neonatal outcomes.

CONCLUSIONS

Reassuringly, the colour-coded CTG classification system was non-inferior to the prose-based system, did not influence OD-IFC but was associated with more spontaneous vaginal deliveries.

Diagnostic capacity and interobserver variability in FIGO, ACOG, NICE and Chandraharan cardiotocographic guidelines to predict neonatal acidemia

OBJECTIVE

Despite its routine use in intrapartum care, the technique of fetal cardiotocography has some limitations. The aim of this study is to analyze the predictive capacity and interobserver agreement in the latest versions of four international cardiotocography guidelines: Federation of Gynecology and Obstetrics (FIGO), American College of Obstetrics and Gynecology (ACOG), the National Institute for Health and Care Excellence (NICE) and Chandraharan, used to predict neonatal acidemia.

STUDY DESIGN

The last 30 min of 150 cardiotocographic records were analyzed over all the pH ranges and were blindly evaluated by three independent reviewers. The sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve (AUC) were calculated to assess the predictive capacity of each fetal cardiotocographic guideline. The degree of interobserver agreement was evaluated with the Fleiss Kappa coefficient.

RESULTS

Observers found fetal cardiotocography guidelines to have a variable sensitivity and specificity. The Chandraharan classification reached the highest sensitivity (78.79%), while ACOG had the highest specificity (95.73%). On average for the three observers, Chandraharan had the highest discrimination capacity for neonatal acidemia, although this was only moderate (AUC 0.66; 95%CI, 0.55-0.77) and did not differ significantly from the remaining guidelines. The degree of agreement among the three observers, assessed according to the Fleiss Kappa coefficient, was generally acceptable or moderate for all items and classifications, being highest with the FIGO classification (ĸ = 0.35; 95%CI, 0.28-0.41) and lowest with the ACOG (ĸ = 0.23; 95%CI, 0.16-0.30).

CONCLUSION

Although all the guidelines have a moderate capacity to predict neonatal acidemia, the Chandraharan guideline has the highest capacity. This follows a different approach from the others in that it relies on interpretations of cardiotocographic traces based on fetal physiology. The degree of interobserver agreement is, in general, acceptable for the four guidelines, and is the highest for FIGO.

Fetal Heart Rate Fragmentation

Intrapartum fetal monitoring's primary goal is to avoid adverse perinatal outcomes related to hypoxia/acidosis without increasing unnecessary interventions. Recently, a set of indices were proposed as new biomarkers to analyze heart rate (HR), termed HR fragmentation (HRF). In this work, the HRF indices were applied to intrapartum fetal heart rate (FHR) traces to evaluate fetal acidemia. The fragmentation method produces four indices: PIP-Percentage of inflection points; IALS-Inverse of the average length of acceleration/deceleration segments; PSS-Percentage of short segments; PAS-Percentage of alternating segments. On the other hand, the symbolic approach studied the existence of different patterns of length four. We applied the measures to 246 selected FHR recordings sampled at 4 and 2 Hz, where 39 presented umbilical artery's pH ≤ 7.15. When applied to the 4 Hz FHR, the PIP, IASL, and PSS showed significantly higher values in the traces from acidemic fetuses. In comparison, the percentage of "words"W 1 h andW 2 s showed lower values for those traces. Furthermore, when using the 2 Hz, only IASL, W 0, andW 2 m achieved significant differences between traces from both acidemic and normal fetuses. Notwithstanding, the ideal sampling frequency is yet to be established. The fragmentation indices correlated with Sisporto variability measures, especially short-term variability. Accordingly, the fragmentation indices seem to be able to detect pathological patterns in FHR tracings. These indices have the advantage of being suitable and straightforward to apply in real-time analysis. Future studies should combine these indexes with others used successfully to detect fetal hypoxia, improving the power of discrimination in a larger dataset.

Impaired validity of the new FIGO and Swedish CTG classification templates to identify fetal acidosis in the first stage of labor

INTRODUCTION

Cardiotocography (CTG) is the main method of intrapartum fetal surveillance. In 2015 a new guideline was introduced by the International Federation of Gynecology and Obstetrics (FIGO), FIGO-15. In Sweden it was adjusted to SWE-17, replacing the previous national template, SWE-09. This study, conducted at one university hospital and one regional hospital in southern Sweden, evaluated the diagnostic validity of these three templates to detect fetal acidosis during the first stage of labor.

MATERIAL AND METHODS

A total of 73 neonates with pH <7.1 in umbilical cord artery or vein at cesarean delivery during the first stage of labor were identified retrospectively. For each acidotic neonate, three non-acidemic neonates, with a pH ≥7.2 in cord artery and vein, and Apgar scores ≥9 at five and ten minutes, in all 219 neonates, were selected. The CTG tracings before birth in acidemic neonates, and tracings at the same cervical dilatation in the non-acidemic neonates, were independently assessed by three professionals from the obstetric staff, blinded to group and clinical data. Based on their categorizations of the included variables (baseline, variability, accelerations, decelerations and contraction rate), each CTG tracing was systematically classified according to the three templates. The sensitivity and specificity to identify acidemia by the classification pathological were determined for each template. Interobserver agreement in the assessments of tracings as pathological or not was analyzed, using free-marginal Kappa index.

RESULTS

The sensitivity for patterns classified as pathological to identify acidemia was similar for FIGO-15 (71%) and SWE-17 (77%, p = .13), and the specificity was 97% for both. SWE-09 had a significantly higher sensitivity (95%, p < .001) albeit with a lower specificity (90%, p < .001) than the other two templates. Among acidemic neonates, the fraction of tracings classified as normal was higher with SWE-17 (9.6%) than with SWE-09 (0%; p = .01) and FIGO-15 (1.4%; p = .06). For tracings from neonates with acidemia, agreement for three independent assessors was strong (κ 0.85) with SWE-09, and weak for FIGO-15 (κ 0.47), and SWE-17 (κ 0.51). For tracings from neonates without acidemia, the agreement was almost perfect for FIGO-15 (κ 0.91), strong withSWE-17 (κ 0.90) and moderate with SWE-09 (κ 0.78).

CONCLUSIONS

The ability of FIGO-15 and SWE-17 to identify fetal acidosis is considered insufficient. The combination of a high sensitivity and a high specificity makes SWE-09 the most discriminatory template during the first stage of labor.

[Normal childbirth: Physiologic labor support and medical procedures. Guidelines of the French National Authority for Health (HAS) with the collaboration of the French College of Gynaecologists and Obstetricians (CNGOF) and the French College of Midwives (CNSF) - Initial assessment on admission and fetal monitoring during labor]

OBJECTIVES

The purpose of this literature's review is to provide recommendations for measures to assess fetal "well-being" at admission and during labor in order to identify a non-reassuring fetal condition.

METHODS

Consultation of the Medline database, and of national and international guidelines.

RESULTS

Two fetal heart rate monitoring techniques are available at admission and during labor. In comparison with intermittent auscultation (AI), continuous cardiotocography (CTG) monitoring was associated, in a meta-analysis involving 13 trials including more than 37,000 women, with a reduction in RR neonatal seizures by half. Relative risk (RR)=0.50 with a 95% CI [0.31-0.80] without significant difference objectified with respect to cerebral palsy RR=1.75 95% CI [0.84-3.63]. In contrast, a significant increase in cesarean sections was associated with continuous CTG RR=1.63 95% CI [1.29-2.07] and women were also at greater risk for operative vaginal delivery RR=1.15 95% CI [1.01-1.33]. Current results are insufficient to demonstrate the actual impact of surveillance methods (continuous or discontinuous) on the overall perinatal mortality rate. Larger randomized trials remain to be conducted.

CONCLUSION

The systematic search for the confirmation of the reassuring character of the fetal state at admission and during labor makes it possible to identify intrapartum hypoxic events.

Low sensitivity of the new FIGO classification system for electronic fetal monitoring to identify fetal acidosis in the second stage of labor

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Cardiotocography interpretation guidelines evaluated during second stage of labor.

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Case-control study including neonates with cord artery acidosis at vaginal delivery.

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Low sensitivity of FIGO intrapartum monitoring guidelines to detect acidosis.

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The Swedish 2009 template had a high sensitivity.

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The Swedish 2017 template had a high sensitivity with cut-off set at suspicious.

Objective

In 2015, new FIGO guidelines for CTG interpretation were presented (FIGO-15). In 2017, the previous Swedish guidelines (SWE-09) were replaced with guidelines adapted to FIGOs (SWE-17). The performance of these three templates had not been scientifically evaluated before its clinical implementation. The objective of this study was to compare the sensitivity and specificity to detect fetal acidosis at birth using these three templates during the second stage of labor.

Study design

This case-control study included 295 neonates with cord blood pH < 7.05 and 591 controls with pH ≥ 7.15, born 2012−2017. Tracings from the last 30−80 min of labor were classified independently by three assessors (midwives, residents and obstetricians), blinded to group and outcome.

Results

The classification pathological using FIGO-15 had a sensitivity of 50 % and specificity of 88 % in detecting fetuses with acidosis. For SWE-17, the sensitivity was 62 % and the specificity 85 %. For SWE-09 the sensitivity was 87 % and the specificity 56 %.

By combining suspicious and pathological patterns the sensitivity for FIGO-15 increased to 97 %, and for SWE-17 to 83 %, whereas the specificity decreased to 23 % and 68 % respectively.

Conclusions

The FIGO classification seemed to be insufficiently discriminative in the second stage of labor; most patterns in acidotic cases were classified as merely suspicious with this template, and the sensitivity of pathological patterns was low at 50 %. Combined pathological and suspicious patterns detected fetal acidosis at a specificity that was too low to be useful (23 %). SWE-09 showed the best ability to detect acidosis with pathological patterns (sensitivity 87 %). SWE-17 reached almost the same sensitivity (83 %) with the combination of suspicious and pathological patterns, and at a higher specificity (68 %).

How common is substandard obstetric care in adverse events of birth asphyxia, shoulder dystocia and postpartum hemorrhage? Findings from an external inspection of Norwegian maternity units

Introduction

The Norwegian Board of Health Supervision inspects healthcare institutions to ensure safety and quality of health and welfare services. A planned inspection of 12 maternity units aimed to investigate the practice of obstetric care in the case of birth asphyxia, shoulder dystocia and severe postpartum hemorrhage.

Material and methods

The inspection was carried out at two large, four medium and six small maternity units in Norway in 2016 to investigate adverse events that occurred between 1 January and 31 December 2014. Six of them were selected as control units. The Norwegian Board of Health Supervision searched the Medical Birth Registry of Norway to identify adverse events in each of the categories and then requested access to the medical records for all patients identified. Information about guidelines, formal teaching and simulation training at each unit was obtained by sending a questionnaire to the obstetrician in charge of each maternity unit.

Results

The obstetric units inspected had 553 serious adverse events of birth asphyxia, shoulder dystocia or severe postpartum hemorrhage among 17 323 deliveries. Twenty‐nine events were excluded from further analysis due to erroneous coding or missing data in the patients’ medical records. We included 524 cases (3.0% of all deliveries) of adverse events in the final analysis. Medical errors caused by substandard care were present in 295 (56.2%) cases. There was no difference in the prevalence of substandard care among the maternity units according to their size. Surprisingly, we found significantly fewer cases with substandard care in the units which the supervisory authorities considered particularly risky before the inspection, compared with the control units. Seven of the 12 units had regular formal teaching and training arrangements for obstetric healthcare personnel as outlined in the national guidelines.

Conclusions

Prevalence of adverse events was 3% and similar in all maternity units irrespective of their size. A breach in the standard of care was observed in 56.2% of cases and almost half of the maternity units did not follow national recommendations regarding teaching and practical training of obstetric personnel, suggesting that they should focus on implementing guidelines and training their staff.

Fetal heart rate variability analysis for neonatal acidosis prediction

Fetal well-being during labor is usually assessed by visual analysis of a fetal heart rate (FHR) tracing. Our primary objective was to evaluate the ability of automated heart rate variability (HRV) analysis methods, including our new fetal stress index (FSI), to predict neonatal acidosis. 552 intrapartum recordings were analyzed. The analysis occurred in the last 90 min before birth and was conducted during two 5-min intervals: (i) a stable period of FHR and (ii) the period corresponding to the maximum FSI value. For each period, we computed the mean FHR, FSI, short-term variability (STV), and long-term variability (LTV). Visual FHR interpretation was performed using the FIGO classification. The population was separated into two groups: (i) an acidotic group with an arterial pH at birth ≤ 7.10 and a control group. Prediction of a neonatal pH ≤ 7.10 was assessed by computing the receiver-operating characteristic area under the curve (AUC). FHR, FSI, STV, and LTV did not differ significantly between groups during the stable period. During the FSI max peak period, LTV and STV correlated significantly in the acidotic group (- 5.85 ± 2.19, p = 0.010 and - 0.62 ± 0.29, p = 0.037, respectively). The AUC values were 0.569 for FIGO classification, 0.595 for STV, and 0.622 for LTV. The multivariate model (FIGO, FSI, FC, STV, LTV) had the greatest accuracy for predicting acidosis (AUC = 0.719). FSI was not predictive of neonatal acidosis probably because of the low quality of the FHR signal in cardiotocography. When used separately, HRV indexes and visual FHR analysis were poor predictors of neonatal acidosis. Including all indexes in a multivariate model increased the predictive ability.

Fetal heart rate classification in routine use: Do your prefer a 3-tier or a 5-tier classification?

OBJECTIVE

To assess the current use of a five-tier fetal heart rate (FHR) classification system (National College of French Obstetricians and Gynecologists, CNGOF, 2007) and of a three-tier system (Federation International of Gynecology and Obstetrics, FIGO, 2015).

MATERIALS AND METHODS

This was a single-center prospective study conducted in April 2016. Midwives were asked to classify FHR hourly during their patients' labors according to two classification systems (CNGOF and FIGO). For each system the midwives rated from 0 to 10 the following elements after delivery: ease of FHR classification, the memorization of the classification, access to routine use, and help with the decision of a second-line examination. Finally, they had to choose which classification system seemed most helpful in their clinical practice.

RESULTS

Forty-six patients were included in the study. The median score for the ease of FHR classification according to the CNGOF system was 7, versus 8 according to the FIGO system (p<0.05). The median score for the ease of remembering the classification was 4 for CNGOF versus 8 for FIGO (p<0.05). The FIGO classification system was considered the easiest to use in 76% of cases and the CNGOF system was the most helpful in 61% of cases. The CNGOF system was seen as a help in deciding on a second-line examination in 70% of cases and the FIGO was a help in 63% of cases.

CONCLUSION

The three-tier FIGO classification system seemed easier to use but the five-tier CNGOF classification system was more helpful. The choice of which system to use should be discussed within each medical team.

Gaps in obstetric care processes - we can only improve what is being measured

A multifaceted intervention at all six obstetric units in the Stockholm Health Region was performed in 2008-2011 in order to increase safety for the newborn infants. Case-controlled criterion-based reviews of care processes during labor and delivery have been used to assess factors associated with suboptimal care during labor and delivery. Categories of increased risk of adverse outcome during labor and delivery were defined. Cases with low Apgar scores and healthy controls were scrutinized and compared to data from a study with an identical design performed before the intervention. The risk of suboptimal care increased twice among controls and three times among cases when reviewing specific criteria after a multifaceted intervention. There are still gaps in care processes that need attention. Improving guidelines is important but not enough alone, and the management of fetal surveillance needs further improvement. The complexity of reviewing care processes using criterion-based research methodology is highlighted.

Inter-observer reliability of 4 fetal heart rate classifications

OBJECTIVE

Different classification of fetal heart rate (FHR) pattern have been proposed: FHR classified as either "reassuring" or "non-reassuring", the National Institute of Child Health and Human Development (NICHD) published in 2008 a 3-tier system, the French College of Gynecology and Obstetrics (CNGOF) recommended in 2013 a 5-tier system and recently in 2015, the Federation International of Gynecology and Obstetrics (FIGO) proposed a new classification based on a 3-tier system. Our objective was to assess the inter-observer reliability of these 4 existing classifications.

STUDY DESIGN

Four observers reviewed 100 FHR without clinical information. FHR were obtained from term singleton pregnancies. Fetal heart rate patterns were classified by one 2-tier ("reassuring vs. non-reassuring"), two 3-tier (NICHD 2008 and FIGO 2015), and one 5-tier (CNGOF 2013) fetal heart classifications.

RESULTS

The global agreement between observers was moderate for each classification: 0.58 (0.40-0.74) for the 2-tier, 0.48 (0.37-0.58) for the NICHD 2008, 0.58 (0.53-0.63) for the CNGOF 2013 and 0.59 (0.49-0.67) for the FIGO 2015 classification. When FHR was classified as reassuring, it was classified as normal in 85.5% for the NICHD 2008 and in 94.5% for the FIGO 2015. For the CNGOF 2013, 65.0% were classified as normal and 32.5% as quasi normal. There was strong concordance between FIGO category I and "reassuring" FHR (kappa=0.95).

CONCLUSION

Inter-observer agreement of FHR interpretation is moderate whatever the classification used. To evaluate the superior interest of one classification, it will be interesting to compare their impact on need of second line techniques and on neonatal outcome.

Electronic fetal monitoring, cerebral palsy, and caesarean section: assumptions versus evidence

Given evidence that cerebral palsy is not reduced by electronic fetal monitoring, Karin Nelson, Thomas Sartwelle, and Dwight Rouse ask why routine monitoring and related litigation continue to contribute to high rates of caesarean births

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.

Contributory factors and potentially avoidable neonatal encephalopathy associated with perinatal asphyxia

BACKGROUND

The recently published monograph, Neonatal encephalopathy and neurologic outcome, from the American College of Obstetricians and Gynecologists calls for a root cause analysis to identify components of care that contributed to cases of neonatal encephalopathy to design better practices, surveillance mechanisms, and systems. All cases of infants born in New Zealand with moderate and severe neonatal encephalopathy were reported to the New Zealand Perinatal and Maternal Mortality Review Committee from 2010. A national clinical review of these individual cases has not previously been undertaken.

OBJECTIVES

The objective of the study was to undertake a multidisciplinary structured review of all cases of neonatal encephalopathy that arose following the onset of labor in the absence of acute peripartum events in 2010-2011 to determine the frequency of contributory factors, the proportion of potentially avoidable morbidity and mortality and to identify themes for quality improvement.

STUDY DESIGN

National identification of, and collection of clinical records on, cases of moderate or severe neonatal encephalopathy occurring after the onset of labor in the absence of an acute peripartum event, excluding those with normal gases and Apgar scores at 1 minute, among all cases of moderate and severe neonatal encephalopathy at term in New Zealand in 2010-2011 was undertaken. Cases were included if they had abnormal gases as defined by any of pH of ≤ 7.2, base excess of ≤ -10, or lactate of ≥ 6 or if there were no cord gases, an Apgar score at 1 minute of ≤ 7. A clinical case review was undertaken by a multidisciplinary team using a structured tool to record contributory factors (organization and/or management, personnel, and barriers to access and/or engagement with care), potentially avoidable morbidity and mortality and to identify themes to guide quality improvement.

RESULTS

Eighty-three babies fulfilled the inclusion criteria for the review, 56 moderate (67%) and 27 severe (33%), 21 (25%) of whom were deceased prior to hospital discharge. Eighty-four percent of 64 babies with cord gas results had one of pH of ≤ 7.0, base excess of ≤ -12, or lactate of ≥ 6; and 42% (8 of 19) without cord gases had 5 minute Apgar scores < 5. Excluding 5 babies who died within a day of birth, all but 1 baby were admitted to a neonatal unit within 1 day of birth. Contributory factors were identified in 84% of 83 cases, most commonly personnel factors (76%). Fifty-five percent of cases with morbidity or mortality were considered to be potentially avoidable, and 52% of cases were considered potentially avoidable because of personnel factors. The most frequently identified theme related to the use and interpretation of cardiotocography in labor.

CONCLUSION

A multidisciplinary case review of neonatal encephalopathy following apparently uncomplicated labor identified a high rate of potentially avoidable morbidity and mortality and issues amenable to quality improvement such as multidisciplinary training of staff in fetal surveillance in labor.

SisPorto 4.0 - computer analysis following the 2015 FIGO Guidelines for intrapartum fetal monitoring

SisPorto 4.0 is the most recent version of a program for the computer analysis of cardiotocographic (CTG) signals and ST events, which has been adapted to the 2015 International Federation of Gynaecology and Obstetrics (FIGO) guidelines for intrapartum foetal monitoring. This paper provides a detailed description of the analysis performed by the system, including the signal-processing algorithms involved in identification of basic CTG features and the resulting real-time alerts.

Can Intrapartum Cardiotocography Predict Uterine Rupture among Women with Prior Caesarean Delivery?: A Population Based Case-Control Study

OBJECTIVE

To compare cardiotocographic abnormalities recorded during labour in women with prior caesarean delivery (CD) and complete uterine rupture with those recorded in controls with prior CD without uterine rupture.

STUDY DESIGN

Women with complete uterine rupture during labour between 1997 and 2008 were identified in the Danish Medical Birth Registry (n = 181). Cases were validated by review of medical records and 53 cases with prior CD, trial of labour, available cardiotocogram (CTG) and complete uterine rupture were included and compared with 43 controls with prior CD, trial of labour and available CTG. The CTG tracings were assessed by 19 independent experts divided into groups of three different experts for each tracing. The assessors were blinded to group, outcome and clinical data. They analyzed occurrence of defined abnormalities and classified the traces as normal, suspicious, pathological or pre-terminal according to international guidelines (FIGO).

RESULTS

A pathological CTG during the first stage of labour was present in 77% of cases and in 53% of the controls (OR 2.58 [CI: 0.96-6.94] P = 0.066). Fetal tachycardia was more frequent in cases with uterine rupture (OR 2.50 [CI: 1.0-6.26] P = 0.053). Significantly more cases showed more than 10 severe variable decelerations compared with controls (OR 22 [CI: 1.54-314.2] P = 0.022). Uterine tachysystole was not correlated with the presence of uterine rupture.

CONCLUSION

A pathological cardiotocogram should lead to particular attention on threatening uterine rupture but cannot be considered a strong predictor as it is common in all women with trial of labour after caesarean delivery.

Intra- and interobserver agreement among obstetric experts in court regarding the review of abnormal fetal heart rate tracings and obstetrical management

OBJECTIVE

The objective of the study was to evaluate the intra- and interobserver agreement among obstetric experts in court regarding the retrospective review of abnormal fetal heart rate tracings and obstetrical management of patients with abnormal fetal heart rate during labor.

STUDY DESIGN

A total of 22 French obstetric experts in court reviewed 30 cases of term deliveries of singleton pregnancies diagnosed with at least 1 hour of abnormal fetal heart rate, including 10 cases with adverse neonatal outcome. The experts reviewed all cases twice within a 3-month interval, with the first review being blinded to neonatal outcome. For each case reviewed, the experts were provided with the obstetric data and copies of the complete fetal heart rate recording and the partogram. The experts were asked to classify the abnormal fetal heart rate tracing and to express whether they agreed with the obstetrical management performed. When they disagreed, the experts were asked whether they concluded that an error had been made and whether they considered the obstetrical management as the cause of cerebral palsy in children if any.

RESULTS

Compared with blinded review, the experts were significantly more likely to agree with the obstetric management performed (P < .001) and with the mode of delivery (P < .001) when informed about the neonatal outcome and were less likely to conclude that an error had been made (P < .001) or to establish a link with potential cerebral palsy (P = .003). The experts' intraobserver agreement for the review of abnormal fetal heart rate tracing and obstetrical management were both mediocre (kappa = 0.46-0.51 and kappa = 0.48-0.53, respectively). The interobserver agreement for the review of abnormal fetal heart rate tracing was low and was not improved by knowledge of the neonatal outcome (kappa = 0.11-0.18). The interobserver agreement for the interpretation of obstetrical management was also low (kappa = 0.08-0.19) but appeared to be improved by knowledge of the neonatal outcome (kappa = 0.15-0.32).

CONCLUSION

The intra- and interobserver agreement among obstetric experts in court for the review of abnormal fetal heart rate tracing and the appropriateness of obstetrical care is poor, suggesting a lack of objectivity of obstetrical expertise as currently performed in court.

Continuous cardiotocography during labour: Analysis, classification and management

The use of continuous intrapartum electronic fetal heart rate monitoring (EFM) using a cardiotocograph (CTG) was developed to enable obstetricians and midwives to analyse the changes of fetal heart rate during labour so as to institute timely intervention to avoid intrapartum hypoxic-ischaemic injury. Although CTG was initially developed as a screening tool to predict fetal hypoxia, its positive predictive value for intrapartum fetal hypoxia is approximately only 30%. Even though different international classifications have been developed with the aim of defining combinations of features that help predict intrapartum fetal hypoxia, the false-positive rate of the CTG is high (60%). Moreover, there has not been a demonstrable improvement in the rate of cerebral palsy or perinatal deaths since the introduction of CTG into clinical practice approximately 45 years ago. However, there has been a significant increase in intrapartum caesarean section and operative vaginal delivery rates. Unfortunately, existing guidelines employ the visual interpretation of CTG based on 'pattern recognition', which is fraught with inter- and intra-observer variability. Therefore, clinicians need to understand the physiology behind fetal heart rate changes and to respond to them accordingly, instead of purely relying on guidelines for management. It is very likely that such a 'physiology-based' approach would reduce unnecessary operative interventions and improve perinatal outcomes whilst reducing the need for 'additional tests' of fetal well-being.

Substandard care in delivery-related asphyxia among term infants: prospective cohort study

OBJECTIVE

To assess substandard care factors in the case of delivery-related asphyxia.

DESIGN

Prospective cohort study.

SETTING

Catchment area of the Neonatal Intensive Care Unit (NICU) of the University Medical Center Utrecht; a region in the middle of the Netherlands covering 13% of the Dutch population.

POPULATION

Term infants, without congenital malformations, who died intrapartum or were admitted to the Neonatal Intensive Care Unit due to asphyxia.

METHODS

During a two-year period, cases were prospectively collected and audited by an expert panel.

MAIN OUTCOME MEASURES

Substandard care factors.

RESULTS

37 735 term infants without congenital malformations were born. There were 19 intrapartum deaths, and 89 NICU admissions of which 12 neonates died. In 63 (58%) cases a substandard care factor was identified that was possibly (n= 47, 43%) or probably (n= 16, 15%) related to perinatal death or NICU admission. In primary care, substandard care factors were mainly the low frequency of examination during labor and delay in referral to secondary care. In secondary care, misinterpretation of cardiotocography and failure to respond adequately to clinical signs of fetal distress were the most common substandard care factors.

CONCLUSIONS

Substandard care is present in a substantial number of cases with delivery-related asphyxia resulting in perinatal death or NICU admission. Improving the organization of obstetric care in the Netherlands as well as training of obstetric caregivers might reduce adverse outcomes.

Human factors affecting the interpretation of fetal heart rate tracings: an update

PURPOSE OF REVIEW

Human factors can have an important impact on cardiotocography (CTG) interpretation and management decisions, and therefore may directly affect obstetrical outcomes.

RECENT FINDINGS

It has been well demonstrated that there is wide observer disagreement over CTG interpretation, particularly in the evaluation of variability, decelerations, and overall tracing classification. The reasons behind this are still incompletely understood, but poor reproducibility can have a profound impact on the technology's accuracy and on its efficacy. Some scientific societies have recently revised their guidelines for CTG interpretation, but no up-to-date universally accepted recommendation exists. In spite of some approximation between the major guideline sets, important differences still exist between them, and they remain complex and prone to memory decay. Regular training in CTG interpretation appears to result in increased knowledge, better observer agreement, and improved quality of care. Computer analysis has also been developed, but remains heavily dependent on staff to confirm interpretation and to decide clinical management.

SUMMARY

An international consensus, comprising simpler and more objective interpretation guidelines, together with regular staff training, and improved decision support systems seem to be the way forward for this technology.