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

Double-sided asymmetric method for automated fetal heart rate baseline calculation

The fetal heart rate (FHR) signal is used to assess the well-being of a fetus during labor. Manual interpretation of the FHR is subject to high inter- and intra-observer variability, leading to inconsistent clinical decision-making. The baseline of the FHR signal is crucial for its interpretation. An automated method for baseline determination may reduce interpretation variability. Based on this claim, we present the Auto-Regressed Double-Sided Improved Asymmetric Least Squares (ARDSIAsLS) method as a baseline calculation algorithm designed to imitate expert obstetrician baseline determination. As the FHR signal is prone to a high rate of missing data, a step of gap interpolation in a physiological manner was implemented in the algorithm. The baseline of the interpolated signal was determined using a weighted algorithm of two improved asymmetric least squares smoothing models and an improved symmetric least squares smoothing model. The algorithm was validated against a ground truth determined from annotations of six expert obstetricians. FHR baseline calculation performance of the ARDSIAsLS method yielded a mean absolute error of 2.54 bpm, a max absolute error of 5.22 bpm, and a root mean square error of 2.89 bpm. In a comparison between the algorithm and 11 previously published methods, the algorithm outperformed them all. Notably, the algorithm was non-inferior to expert annotations. Automating the baseline FHR determination process may help reduce practitioner discordance and aid decision-making in the delivery room.

Using the CAESARE tool in fetal heart rate analysis

BACKGROUND

To evaluate the theoretical impact of the CAESARE decision-making tool (which is based on fetal heart rate) on the rate of cesarean section deliveries and the prevention of metabolic acidosis risk.

METHODS

We conducted an observational, multicenter, retrospective study of all patients from 2018 to 2020 who had a cesarean section at term due to non-reassuring fetal status (NRFS) during labor. Primary outcome criteria were the rate of cesarean section births observed retrospectively compared to the theoretical rate by the CAESARE tool. Secondary outcome criteria were newborn umbilical pH (vaginal and cesarean delivery). A single-blind analysis was carried out in which two experienced midwives used the tool to decide whether to proceed with vaginal delivery or to seek the advice of an obstetric gynecologist (OB-GYN). The OB-GYN subsequently used the tool to decide between a vaginal or cesarean delivery.

RESULTS

Our study included 164 patients. The midwives proposed vaginal delivery in 90.2% of cases (of which 60% were without recourse to an OB-GYN). The OB-GYN proposed vaginal delivery for 141 patients (86%) (p<0.01). We found a difference in the umbilical cord arterial pH. The CAESARE tool affected the rapidity of the decision-making process whether to proceed with a cesarean section delivery of newborns with an umbilical cord arterial pH<7.1. The Kappa coefficient was calculated at 0.62.

CONCLUSIONS

The use of a decision-making tool was shown to reduce the rate of cesarean section births for NRFS while taking the risk of neonatal asphyxiation into account. Future prospective studies to assess whether the tool can reduce the cesarean rate without affecting the outcome of newborns should be conducted.

Investigating the interpretability of fetal status assessment using antepartum cardiotocographic records

BACKGROUND

Cardiotocography (CTG) interpretation plays a critical role in prenatal fetal monitoring. However, the interpretation of fetal status assessment using CTG is mainly confined to clinical research. To the best of our knowledge, there is no study on data analysis of CTG records to explore the causal relationships between the important CTG features and fetal status evaluation.

METHODS

For analyses, 2126 cardiotocograms were automatically processed and the respective diagnostic features measured by the Sisporto program. In this paper, we aim to explore the causal relationships between the important CTG features and fetal status evaluation. First, we utilized data visualization and Spearman correlation analysis to explore the relationship among CTG features and their importance on fetal status assessment. Second, we proposed a forward-stepwise-selection association rule analysis (ARA) to supplement the fetal status assessment rules based on sparse pathological cases. Third, we established structural equation models (SEMs) to investigate the latent causal factors and their causal coefficients to fetal status assessment.

RESULTS

Data visualization and the Spearman correlation analysis found that thirteen CTG features were relevant to the fetal state evaluation. The forward-stepwise-selection ARA further validated and complemented the CTG interpretation rules in the fetal monitoring guidelines. The measurement models validated the five latent variables, which were baseline category (BCat), variability category (VCat), acceleration category (ACat), deceleration category (DCat) and uterine contraction category (UCat) based on fetal monitoring knowledge and the above analyses. Furthermore, the interpretable models discovered the cause factors of fetal status assessment and their causal coefficients to fetal status assessment. For instance, VCat could predict BCat, and UCat could predict DCat as well. ACat, BCat and DCat directly affected fetal status assessment, where ACat was the important causal factor.

CONCLUSIONS

The analyses revealed the interpretation rules and discovered the causal factors and their causal coefficients for fetal status assessment. Moreover, the results are consistent with the computerized fetal monitoring and clinical knowledge. Our approaches are conducive to evidence-based medical research and realizing intelligent fetal monitoring.

Intrapartal cardiotocographic patterns and hypoxia-related perinatal outcomes in pregnancies complicated by gestational diabetes mellitus

AIMS

In previous reports, cardiotocographic (CTG) fetal heart rate (FHR) monitoring has shown only limited benefits in decreasing adverse perinatal outcomes in pregnancies complicated by gestational diabetes mellitus (GDM). The aim of the present study was to evaluate whether an association exists between the recently reported ZigZag pattern (FHR baseline amplitude changes of > 25 bpm with a duration of 2-30 min) and asphyxia-related neonatal outcomes in GDM pregnancies.

METHODS

Intrapartal CTGs were recorded in a one-year cohort of 5150 singleton childbirths. The following CTG changes were evaluated: ZigZag pattern, saltatory pattern, late decelerations, episodes of tachycardia and bradycardia, reduced variability, and uterine tachysystole. The cohort was divided into three groups: women with GDM, women with normal oral glucose tolerance test (OGTT), and women with no OGTT performed. Umbilical artery (UA) blood gases, Apgar scores, neonatal respiratory distress, and neonatal encephalopathy were used as outcome variables.

RESULTS

GDM was diagnosed in 624 (12.1%), OGTT was normal in 4115 (79.9%), and OGTT was not performed in 411 (8.0%) women. Hypoxia-related ZigZag patterns (OR 1.94, 95% CI 1.64-2.34) and late decelerations (OR 1.65, 95% CI 1.27-2.13) of FHR, as well as a greater risk of fetal asphyxia (UA pH < 7.10 and/or UA BE < -12.0 meq/L and/or Apgar scores < 7 at 5-min) (OR 6.64, 95% CI 1.84-12.03) were observed in those with GDM compared with those without GDM.

CONCLUSIONS

GDM is associated with intrapartal ZigZag pattern and late decelerations, cord blood acidemia and low 5-min Apgar scores at birth indicating increased occurrence of fetal hypoxia in GDM pregnancies.

[Management of fetal growth restriction in France: Survey of teaching hospitals and tertiary referral centers]

OBJECTIVES

French Guidelines on Fetal Growth Restriction (FGR) were published in December 2013. It seemed interesting to us to carry out an inventory on the management of FGR in teaching hospitals and tertiary referral centers MATERIAL AND METHODS: We carried out a retrospective survey on the academic year 2020/2021. All teaching hospitals and level III maternity in mainland France were contacted (67). The questionnaire focused on the growth curves used, the etiological assessment carried out, the rate and modalities of antenatal surveillance as well as the criteria indicating a birth.

RESULTS

The response rate was 76%. The CFEF curves are used for screening in 78.4% of centers and in the event of FGR in 39.2% of them. The etiological assessment includes a referent ultrasound in 62.7% of cases and amniocentesis is offered in 74.5% of hospitals in case of severe and early FGR. All centers use umbilical Doppler for FGR. The fetal heart rate is monitored between once a week to three times a day in the event of cerebro-placental redistribution. In case of reverse flow, birth is induced from 28 weeks on for some teams while others continue the pregnancy until 39 weeks. In case of cessation of fetal growth, the expected terms of birth are between 28 and 38 weeks.

CONCLUSION

There is great heterogeneity in the management of FGR, particularly in terms of antenatal surveillance and the term of birth envisaged.

The Association between Maternal Race and Ethnicity and Risk Factors for Primary Cesarean Delivery in Nulliparous Women

OBJECTIVE

To understand whether maternal, perinatal, and systems-level factors can be identified to explain racial/ethnic disparities in cesarean delivery rates.

STUDY DESIGN

This retrospective cohort study included nulliparous women with singleton gestations who delivered at a tertiary care center from 2015 to 2017. Maternal, perinatal, and systems-level factors were compared by race/ethnicity. Multilevel multivariable logistic regression was used to identify whether race/ethnicity was independently associated with cesarean. Effect modification was evaluated using interaction terms. Bivariable analyses and multinomial logistic regression were used to determine differences in indication for cesarean.

RESULTS

Of 9,865 eligible women, 2,126 (21.5%) delivered via cesarean. The frequency of cesarean was lowest in non-Hispanic white women (19.2%) and highest in non-Hispanic black women (28.2%; p < 0.001). Accounting for factors associated with cesarean delivery did not lessen the odds of cesarean associated with non-Hispanic black race (aOR: 1.58, 95% CI: 1.31-1.91). Compared with non-Hispanic white women, non-Hispanic black women were more likely to undergo cesarean for nonreassuring fetal status (aOR: 2.73, 95% CI: 2.06-3.61).

CONCLUSION

Examined maternal, perinatal, and systems-level risk factors for cesarean delivery did not explain the racial/ethnic disparities observed in cesarean delivery rates. Increased cesarean delivery for nonreassuring fetal status contributed substantially to this disparity.

Training in the use of intrapartum electronic fetal monitoring with cardiotocography: systematic review and meta‐analysis

Background

Sub‐optimal classification, interpretation and response to intrapartum electronic fetal monitoring using cardiotocography are known problems. Training is often recommended as a solution, but there is lack of clarity about the effects of training and which type of training works best.

Objectives

Systematic review of the effects of training healthcare professionals in intrapartum cardiotocography (PROSPERO protocol: CRD42017064525).

Search strategy

CENTRAL, Cochrane Library, MEDLINE, EMBASE, PsycINFO, British Nursing Database, CINAHL, ERIC, Scopus, Web of Science, ProQuest, grey literature and ongoing clinical trials were searched.

Selection criteria

Primary studies that reported impact of training healthcare professionals in intrapartum cardiotocography. Title/abstract, full‐text screening and quality assessment were conducted in duplicate.

Data collection and analysis

Data were synthesised both narratively and using meta‐analysis. Risk of bias and overall quality were assessed with the Mixed Methods Appraisal Tool and GRADE.

Main results

Sixty‐four studies were included. Overall, training and reporting were heterogeneous, the outcomes evaluated varied widely and study quality was low. Five randomised controlled trials reported that training improved knowledge of maternity professionals compared with no training, but evidence was of low quality. Evidence for the impact of cardiotocography training on neonatal and maternal outcomes was limited, showed inconsistent effects, and was of low overall quality. Evidence for the optimal content and method of delivery of training was very limited.

Conclusions

Given the scale of harm and litigation claims associated with electronic fetal monitoring, the evidence‐base for training requires improvement. It should address intervention design, evaluation of clinical outcomes and system‐wide contexts of sub‐optimal practice.

Tweetable abstract

Training in fetal monitoring: systematic review finds little evidence of impact on neonatal outcomes.

Training in fetal monitoring: systematic review finds little evidence of impact on neonatal outcomes.

Factors associated with intrapartum ZigZag pattern of fetal heart rate: A retrospective one-year cohort study of 5150 singleton childbirths

OBJECTIVES

Recent studies suggest that intrapartum ZigZag pattern of fetal heart rate (FHR) is significantly associated with cord blood acidaemia and neonatal complications. For the clinical significance of this pattern, it is mandatory that ZigZag episodes in cardiotocographic (CTG) recording are correctly identified. The aim of the present study was to examine maternal, fetal and delivery-related factors that could explain the occurrence of ZigZag pattern of FHR during the last 2 h of labour in a large obstetric cohort.

STUDY DESIGN

CTG recordings from 5150 singleton childbirths at ≥33 weeks of gestation during one year were evaluated retrospectively and blinded to pregnancy and neonatal outcomes in a university hospital in Helsinki, Finland. All women in the cohort were in the active phase of labour with regular uterine contractions. ZigZag FHR pattern was defined as FHR baseline amplitude changes of >25 bpm with a duration of 2-30 min. The following maternal, fetal and labour/delivery-related variables were determined: maternal age, obesity (prepregnancy BMI ≥ 30.0 kg/m²), parity, preeclampsia, maternal fever ≥38.0 °C, smoking, gestational age at delivery, fetal sex, birth weight z-score, mode of delivery, and type of onset of labour.

RESULTS

ZigZag pattern occurred in 582/5150 (11.3 %) cases, and only in childbirths after 37 weeks of gestation. Fetal male gender (OR 3.29; 95 % CI 2.70-4.02), nulliparous pregnancy (OR 2.60; 95 % CI 2.15-3.15) and post-term gestational age (≥42 weeks) (OR 1.92; 95 % CI 1.47-2.48) were independently associated with the occurrence of ZigZag pattern. Among the three significant risk factors, clustering of two or three factors was associated with an increase of the ZigZag pattern occurrence risk to 5.0-16.4-fold (95 % CI 3.16-31.60).

CONCLUSIONS

ZigZag pattern occurred in term pregnancies after 37 weeks of gestation only. Fetal male gender, nulliparity and post-term pregnancy are significantly associated with ZigZag FHR pattern during the last two hours of labour. Identification of maternal, fetal and delivery-related variables are imperative in order to interpret correctly the findings of CTG and to prevent adverse neonatal outcome.

Fetal physiology cardiotocography training, a regional evaluation

INTRODUCTION

Cardiotocography (CTG) has its limits in detecting fetal acidosis and intrapartum asphyxia. Our aim was to evaluate a CTG training programme based on fetal physiology in the Mediterranean perinatal network.

METHODS

Professionals from 41 maternity units of the Mediterranean network were invited to participate in a CTG masterclass based on fetal physiology in March 2019 and October 2019. They were asked to react to three practical cases by a physiological approach before the training course (T0), one month after (T1) and six to seven months after (T2). The mean scores were compared by using a mixed model including lapse of time to evaluation, profession of participants and level of the maternity unit as fixed effects.

RESULTS

A total of 248 professionals from 32 maternity units finally participated in the organizational audit. By using a mixed model, we found a significant improvement of the mean score at T1=6.44/10 compared to T0=4.97/10 (p<0.0001), and a significant improvement of the mean score obtained at T2=6.17/10 compared to T0 (p<0.0001). T2 scores were not significantly different from T1 scores (p=0.143).

DISCUSSION

A CTG training programme based on fetal physiology showed a significant improvement in the professionals' interpretation of CTG at short term and stable results at long term. Continuing medical education could help maintain and improve knowledge to ensure neonatal safety.

[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.

Intrapartum zigzag pattern of fetal heart rate is an early sign of fetal hypoxia: A large obstetric retrospective cohort study

Introduction

The aim of the present study was to identify possible associations of fetal heart rate (FHR) patterns during the last 2 hours of labor with fetal asphyxia expressed by umbilical artery acidemia at birth and with neonatal complications in a large obstetric cohort.

Material and methods

Cardiotocographic recordings from 4988 singleton term childbirths over 1 year were evaluated retrospectively and blinded to the pregnancy and neonatal outcomes in a university teaching hospital in Helsinki, Finland. Umbilical artery pH, base excess and pO₂, low Apgar scores at 5 minutes, need for intubation and resuscitation, early neonatal hypoglycemia, and neonatal encephalopathy were used as outcome variables. According to the severity of the neonatal complications at birth, the cohort was divided into three groups: no complications (Group 1), moderate complications (Group 2) and severe complications (Group 3).

Results

Of the 4988 deliveries, the ZigZag pattern (FHR baseline amplitude changes of >25 bpm with a duration of 2‐30 minutes) occurred in 11.7%, late decelerations in 41.0%, bradycardia episodes in 52.9%, reduced variability in 36.7%, tachycardia episodes in 13.9% and uterine tachysystole in 4.6%. No case of saltatory pattern (baseline amplitude changes of >25 bpm with a duration of >30 minutes) was observed. The presence of the ZigZag pattern or late decelerations, or both, was associated with cord blood acidemia (odds ratio [OR] 3.3, 95% confidence interval [CI] 2.3‐4.7) and severe neonatal complications (Group 3) (OR 3.3, 95% CI 2.4‐4.9). In contrast, no significant associations existed between the other FHR patterns and severe neonatal complications. ZigZag pattern preceded late decelerations in 88.7% of the cases. A normal FHR preceded the ZigZag pattern in 90.4% of the cases, whereas after ZigZag episodes, a normal FHR pattern was observed in only 0.9%.

Conclusions

ZigZag pattern and late decelerations during the last 2 hours of labor are significantly associated with cord blood acidemia at birth and neonatal complications. The ZigZag pattern precedes late decelerations, and the fact that normal FHR pattern precedes the ZigZag pattern in the majority of the cases suggests that the ZigZag pattern is an early sign of fetal hypoxia, which emphasizes its clinical importance.

Differences in rate and medical indication of caesarean section between Germany and Japan

BACKGROUND

There are growing concerns about the increasing rate of caesarean section (CS) worldwide. Various strategies have been implemented to reduce the proportion of CS to a reasonable level. Most research on medical indications for CS focuses on nationwide evaluations. Comparative research between different countries is sparse. The aim of this study was to evaluate differences in the rate and indications for CS between Japan and Germany in 2012 and 2013.

METHODS

Comparison of the overall rate and medical indications for CS in two cohort studies from Germany and Japan. We used data from the German Perinatal Survey and the Japan Environment and Children's Study (JECS).

RESULTS

We analyzed data of 1 335 150 participants from the German perinatal survey and of 62 533 participants from JECS and found significant differences between the two countries in CS rate (30.6% vs 20.6%) and main medical indications: cephalopelvic disproportion (3.2% vs 1.3%; OR: 2.4 [95% CI: 2.2-2.6]), fetal distress (7.3% vs 2.3%; OR: 3.4 [95%-CI: 3.2-3.6]), and past uterine surgery/repeat CS (8.4% vs 8.8%; OR: 0.9 [95%-CI: 0.9-1]).

CONCLUSION

There are differences in the rate and medical indications for CS between Germany and Japan at the population level. Fetal distress was identified as a medical indication for CS more often Germany than in Japan. Considering the substantial diagnostic uncertainty of electronic fetal monitoring (EFM) as the major indicator for fetal distress, it would seem to be reasonable to rethink CS decision algorithms.

Intrapartum fetal monitoring and perinatal risk factors of neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy (HIE) in term infants, is a major cause of neonatal mortality and severe neurologic disability.

OBJECTIVES

To identify in labor fetal monitoring characteristic patterns and perinatal factors associated with neonatal HIE.

STUDY DESIGN

Single-center retrospective case-control study between 2010 and 2017. Cases clinically diagnosed with neonatal HIE treated by therapeutic hypothermia according to strict criteria (HIE-TH) were compared to a group of neonates born in the same period, gestational age-matched diagnosed with fetal distress according to fetal monitoring interpretation that was followed by prompt delivery, without subsequent HIE or therapeutic hypothermia (No-HIE). The primary outcome of the study was the electronic fetal monitoring (EFM) pattern during 60 min prior to delivery; the secondary outcome was the identification of perinatal associated factors.

RESULTS

54 neonates with HIE were treated by therapeutic hypothermia. EFM parameters most predictive of HIE-TH were indeterminate baseline heart rate OR = 47.297, 95% (8.17-273.76) p < 0.001, bradycardia OR = 15.997 95% (4.18-61.18) p < 0.001, low variability OR = 10.224, 95% (2.71-38.45) p < 0.001, higher baseline of the fetal heart rate calculated for each increment of 1 BPM OR = 1.0547, 95% (1.001-1.116) p = 0.047. Rupture of a previous uterine cesarean scar and placental abruption were characteristic of the HIE-TH group 14.8% vs. 1% p < 0.05; and 16.7% vs. 6% p < 0.05, respectively. Adverse neonatal outcomes also differed significantly: HIE-TH had a higher rate of neonatal seizures 46.2% vs. 0% p < 0.001 and mortality 7.7% vs. 0% p < 0.001.

CONCLUSIONS

Characteristic fetal monitoring pattern prior to delivery together with acute obstetric emergency events are associated with neonatal HIE, neurological morbidity, and mortality.

Validation of a Novel Transabdominal Fetal Oximeter in a Hypoxic Fetal Lamb Model

Current intrapartum fetal oxygen saturation (SaO2) monitoring methodologies are limited, mostly consisting of fetal heart rate monitoring which is a poor predictor of fetal hypoxia. A newly developed transabdominal fetal oximeter (TFO) may be able to determine fetal SaO2 non-invasively. This study is to validate a novel TFO in determining fetal SaO2 in a hypoxic fetal lamb model. Fetal hypoxia was induced in at-term pregnant ewe by placing an aortic occlusion balloon infrarenally and inflating it in a stepwise fashion to decrease blood flow to the uterine artery. The inflation was held at each step for 10 min, and fetal arterial blood gases (ABGs) were intermittently recorded from the fetal carotid artery. The balloon catheter was deflated when fetal SaO2 fell below 15%, and the fetus was recovered. A total of three desaturation experiments were performed. The average fetal SpO2 reported by the TFO was derived at each hypoxic level and correlated with the ABG measures. Fetal SaO2 from the ABGs ranged from 10.5 to 66%. The TFO SpO2 correlated with the ABG fetal SaO2 (r-squared = 0.856) with no significant differences (p > 0.5). The fetal SpO2 measurements from TFO were significantly different than the maternal SpO2 (p < 0.01), which suggests that the transcutaneous measurements are penetrating through the maternal abdomen sufficiently and are expressing the underlying fetal tissue physiology. The recently developed TFO system was able to non-invasively report the fetal SpO2, which showed strong correlation with ABG measures and showed no significant differences.

[Comparison of antepartum management of breech versus cephalic presentation]

OBJECTIVES

Delivery mode of term breech presentation is still being discussed. The aim of this study was to compare the labor management of a breech presentation to a vertex presentation during a vaginal delivery attempt.

METHODS

It was a single-center, comparative, descriptive retrospective study from 2014 to 2017. We studied fetal heart rate (FHR) during labor and expulsion, duration of the different stage of labor, mode of delivery and neonatal outcomes for breech and vertex presentations.

RESULTS

Two hundred and thirty-nine patients were included whom 106 (44%) breech presentation. The use of oxytocin was more common in breech group (63,2% versus 48,1%, P=0.020). Average dilatation rate was slower for breech presentation than for vertex presentation (1.9cm/h vs. 2.8cm/h; P=0.005). There was more FHR with high risk of acidosis in the breech presentations (37.2% vs 19.1%, P=0.001) and Melchior's FHR classification were comparable in both groups.

CONCLUSIONS

The per-partum management of a fetus in breech presentation differs from a fetus in cephalic presentation. It must be known and anticipated for an optimal management in the delivery room.

Fetal electrocardiography ST-segment analysis for intrapartum monitoring: a critical appraisal of conflicting evidence and a way forward

BACKGROUND

In the past century, some areas of obstetric including intrapartum care have been slow to benefit from the dramatic advances in technology and medical care. Although fetal heart rate monitoring (cardiotocography) became available a half century ago, its interpretation often differs between institutions and countries, its diagnostic accuracy needs improvement, and a technology to help reduce the unnecessary obstetric interventions that have accompanied the cardiotocography is urgently needed.

STUDY DESIGN

During the second half of the 20th century, key findings in animal experiments captured the close relationship between myocardial glycogenolysis, myocardial workload, and ST changes, thus demonstrating that ST waveform analysis of the fetal electrocardiogram can provide information on oxygenation of the fetal myocardium and establishing the physiological basis for the use of electrocardiogram in intrapartum fetal surveillance.

RESULTS

Six randomized controlled trials, 10 meta-analyses, and more than 20 observational studies have evaluated the technology developed based on this principle. Nonetheless, despite this intensive assessment, differences in study protocols, inclusion criteria, enrollment rates, clinical guidelines, use of fetal blood sampling, and definitions of key outcome parameters, as well as inconsistencies in randomized controlled trial data handling and statistical methodology, have made this voluminous evidence difficult to interpret. Enormous resources spent on randomized controlled trials have failed to guarantee the generalizability of their results to other settings or their ability to reflect everyday clinical practice.

CONCLUSION

The latest meta-analysis used revised data from primary randomized controlled trials and data from the largest randomized controlled trials from the United States to demonstrate a significant reduction of metabolic acidosis rates by 36% (odds ratio, 0.64; 95% confidence interval, 0.46-0.88) and operative vaginal delivery rates by 8% (relative risk, 0.92; 95% confidence interval, 0.86-0.99), compared with cardiotocography alone.

Cumulative deceleration area: a simplified predictor of metabolic acidemia

OBJECTIVE

Fetal monitoring, ubiquitous in obstetrics is used to predict and prevent intrapartum fetal injury. Despite decades of education and nomenclature revision, clinicians show low agreement on key elements, including the types of deceleration and hence their presumed etiology. Cumulative deceleration area is not dependent on deceleration type and could potentially mitigate this problem. Although deceleration area has shown promise as a marker of acidemia, no reports have shown how deceleration area evolves in late labor. Advances in computerization allow for direct measurement of deceleration area and standard fetal heart rate (FHR) patterns. The objective of this study was to compare the evolution and discrimination performance of deceleration area and other FHR patterns in late labor in term neonates with metabolic acidemia (MA) and in those with normal cord gases.

METHODS

This retrospective cohort study included women with a term singleton (≥37 weeks) in cephalic presentation with cord gas data and FHR tracings available for analysis. MA included neonates with an umbilical artery base deficit >12 mmol/L (n = 132). Controls included those with normal cord gases (base deficit <8 mmol/L) and a 5-minute Apgar score of >6 (n = 1498). Deceleration area and other FHR patterns were summarized and compared in 30-minute segments over the last five hours. Receiver-operating characteristic curves were constructed and AUCs compared.

RESULTS

Deceleration area had the highest AUC (0.702, 95% CI 0.655-0.749) and was a superior marker of MA compared to baseline (AUC 0.588, 95% CI 0.530-0.645), baseline variability (AUC 0.611, 95% CI 0.558-0.663), and number of late decelerations (AUC 0.582, 95% CI 0.527-0.637).

CONCLUSION

Cumulative deceleration area reduces the necessity to determine deceleration type. In a single number, it objectively quantifies three important aspects of decelerations; frequency, depth and duration and was a superior marker of MA compared to baseline level, baseline variability and number of late decelerations. The acidemia group had higher deceleration area over the last two hours prior to delivery. This result indicates that the cumulative area and persistence of repetitive decelerations is important clinically.

Fetal heart rate baseline computation with a weighted median filter

BACKGROUND

Automated fetal heart rate (FHR) analysis removes inter- and intra-expert variability, and is a promising solution for reducing the occurrence of fetal acidosis and the implementation of unnecessary medical procedures. The first steps in automated FHR analysis are determination of the baseline, and detection of accelerations and decelerations (A/D). We describe a new method in which a weighted median filter baseline (WMFB) is computed and A/Ds are then detected.

METHOD

The filter weightings are based on the prior probability that the sampled FHR is in the baseline state or in an A/D state. This probability is computed by estimating the signal's stability at low frequencies and by progressively trimming the signal. Using a competition dataset of 90 previously annotated FHR recordings, we evaluated the WMFB method and 11 recently published literature methods against the ground truth of an expert consensus. The level of agreement between the WMFB method and the expert consensus was estimated by calculating several indices (primarily the morphological analysis discordance index, MADI). The agreement indices were then compared with the values for eleven other methods. We also compared the level of method-expert agreement with the level of interrater agreement.

RESULTS

For the WMFB method, the MADI indicated a disagreement of 4.02% vs. the consensus; this value is significantly lower (p<10^-13) than that calculated for the best of the 11 literature methods (7.27%, for Lu and Wei's empirical mode decomposition method). The level of inter-expert agreement (according to the MADI) and the level of WMFB-expert agreement did not differ significantly (p=0.22).

CONCLUSION

The WMFB method reproduced the expert consensus analysis better than 11 other methods. No differences in performance between the WMFB method and individual experts were observed. The method Matlab source code is available under General Public Licence at http://utsb.univ-catholille.fr/fhr-wmfb.

IMproving the practice of intrapartum electronic fetal heart rate MOnitoring with cardiotocography for safer childbirth (the IMMO programme): protocol for a qualitative study

INTRODUCTION

Suboptimal electronic fetal heart rate monitoring (EFM) in labour using cardiotocography (CTG) has been identified as one of the most common causes of avoidable harm in maternity care. Training staff is a frequently proposed solution to reduce harm. However, current approaches to training are heterogeneous in content and format, making it difficult to assess effectiveness. Technological solutions, such as digital decision support, have not yet demonstrated improved outcomes. Effective improvement strategies require in-depth understanding of the technical and social mechanisms underpinning the EFM process. The aim of this study is to advance current knowledge of the types of errors, hazards and failure modes in the process of classifying, interpreting and responding to CTG traces. This study is part of a broader research programme aimed at developing and testing an intervention to improve intrapartum EFM.

METHODS AND ANALYSIS

The study is organised into two workstreams. First, we will conduct observations and interviews in three UK maternity units to gain an in-depth understanding of how intrapartum EFM is performed in routine clinical practice. Data analysis will combine the insights of an ethnographic approach (focused on the social norms and interactions, values and meanings that appear to be linked with the process of EFM) with a systems thinking approach (focused on modelling processes, actors and their interactions). Second, we will use risk analysis techniques to develop a framework of the errors, hazards and failure modes that affect intrapartum EFM.

ETHICS AND DISSEMINATION

This study has been approved by the West Midlands-South Birmingham Research Ethics Committee, reference number: 18/WM/0292. Dissemination will take the form of academic articles in peer-reviewed journals and conferences, along with tailored communication with various stakeholders in maternity care.

Threshold of metabolic acidosis associated with newborn cerebral palsy: medical legal implications

Obstetricians and gynecologists belong to 1 of the medical specialties with the highest rate of litigation claims. Among birth injury cases, those cases with cerebral palsy outcomes account for litigation settlements or judgments often in the millions of dollars. In cases of potential perinatal asphyxia, a threshold level of metabolic acidosis (base deficit ≥12 mmol/L) is necessary to attribute neonatal encephalopathy to an intrapartum hypoxic event. With increasing duration or severity of a hypoxic stress resulting in metabolic acidosis, newborn infant umbilical artery base deficit increases. It may be alleged that, as base deficit levels increase beyond 12 mmol/L, there is an increased likelihood and severity of cerebral palsy. As a corollary, it may be claimed that an earlier delivery (by minutes) would reduce the base deficit and prevent or reduce the severity of cerebral palsy. This issue is of relevance to obstetricians as defendants, because retrospective "expert" analysis of cases may suggest that optimal management decisions would have resulted in an earlier delivery. In addressing the association of metabolic acidosis and cerebral palsy, base deficit should be measured as the extracellular component (base deficit_{extracellular fluid}) rather than the commonly used base deficit_blood. Studies suggest that, beyond the base deficit threshold of 12 mmol/L, the incidence and severity of cerebral palsy does not significantly increase (until ≥20 mmol/L), although the risk of neonatal death rises markedly. Thus, among most infants with hypoxia-associated neonatal encephalopathy, the occurrence of cerebral palsy is unlikely to be impacted by delivery time variation of few minutes, and this argument should not serve as the basis for medical legal claims.

Baseline fetal heart rate analysis: eleven automatic methods versus expert consensus

Visual analysis of fetal heart rate (FHR) during labor is subject to inter- and intra-observer variability that is particularly troublesome for anomalous recordings. Automatic FHR analysis has been proposed as a promising way to reduce this variability. The major difficulty with automatic analysis is to determine the baseline from which accelerations and decelerations will be detected. Eleven methods for automatic FHR analysis were reprogrammed using description from the literature and applied to 66 FHR recordings collected during the first stage of delivery. The FHR baselines produced by the automatic methods were compared with the baseline defined by agreement among a panel of three experts. The better performance of the automatic methods described by Mongelli, Lu, Wrobel and Pardey was noted despite their different approaches on signal processing. Nevertheless, for several recordings, none of the automatic studied methods produced a baseline similar to that defined by the experts.

Reliability in cardiotocography interpretation - impact of extended on-site education in addition to web-based learning: an observational study

INTRODUCTION

Previous studies have shown poor reproducibility in cardiotocography (CTG) interpretation. Studies evaluating the Swedish web-based CTG-education program have not proven to increase accurate CTG assessments. The aim of this study was to evaluate whether an extended education can improve inter- and intra-observer reliability in CTG interpretation.

MATERIAL AND METHODS

Six obstetricians from two different departments interpreted 106 CTG tracings on two occasions. Both departments used a Swedish national web-based CTG education and test for training. One department had, in addition, an extended education program consisting of on-site lectures and oral examinations. Inter- and intra-observer agreements were calculated by simple or weighted kappa (κ) values for the five parameters assessed on CTG.

RESULTS

In both departments inter-observer and intra-observer κ showed moderate to excellent agreement (ranges for κ 0.41-0.76 and 0.65-0.93, respectively). Obstetricians at the department with extended CTG education had better inter-observer reliability for variability and accelerations. This was also the case for intra-observer reliability with the addition of baseline frequency. Both inter- and intra-observer agreement increased from moderate to substantial in both departments when decelerations were dichotomized into harmless (including early and simple variable decelerations) or hypoxic (including late, severe variable, prolonged and combined decelerations) (κ 0.63-0.78) compared with the current sub-classification of decelerations (κ 0.42-0.65).

CONCLUSIONS

Agreement in CTG interpretation was better than expected in both departments, especially when divided into harmless/hypoxic changes. Combination of different learning methods (web-based, on-site lectures and case discussion) might result in a better CTG interpretation agreement compared with web-based learning solely.

Neurological Fallacies Leading to Malpractice: A Case Studies Approach

A young woman presents with an intracranial arachnoid cyst. Another is diagnosed with migraine headache. An elderly man awakens with a stroke. And a baby delivered vaginally after 2 hours of questionable electronic fetal monitoring patterns grows up to have cerebral palsy. These seemingly disparate cases share a common underlying theme: medical myths. Myths that may lead not only to misdiagnosis and treatment harms but to seemingly never-ending medical malpractice lawsuits, potentially culminating in a settlement or judgment against an unsuspecting neurologist. This article provides a case studies approach exposing the fallacies and highlighting proper management of these common neurologic presentations.