Intrapartum Fetal Heart Rate Tracings Research Articles

Interobserver Agreement and Reliability of Intrapartum Nonreassuring Cardiotocography and Prediction of Neonatal Acidemia

Abstract Objective: To evaluate the agreement and reliability of intrapartum nonreasurring cardiotocography (CTG) interpretation and prediction of neonatal acidemia by obstetricians working in different centers. Methods: A retrospective cohort study involving two tertiary hospitals (The First Affiliated Hospital of Sun Yat-sen University and Perking University Third Hospital) was conducted between 30th September 2018 and 1st April 2019. Six obstetricians from two hospitals with three levels of experience (junior, medium, and senior) reviewed 100 nonreassuring fetal heart rate (FHR) tracings from 1 hour before the onset of abnormalities until delivery. Each reviewer determined the FHR pattern, the baseline, variability, and presence of acceleration, deceleration, sinusoidal pattern, and predicted whether neonatal acidemia and abnormal umbilical arterial pH < 7.1 would occur. Inter-observer agreement was assessed using the proportions of agreement (Pa) and the proportion of specific agreement (Pa for each category). Reliability was evaluated with the kappa statistic (k-Light's kappa for n raters) and Gwet's AC1 statistic. Results: Good inter-observer agreement was found in evaluation of most variables (Pa > 0.5), with the exception of early deceleration (Pa = 0.39, 95% confidence interval (CI): 0.36,0.43). Reliability was also good among most variables (AC1 > 0.40), except for acceleration, early deceleration, and prediction of neonatal acidemia (AC1 = 0.17, 0.10, and 0.25, respectively). There were no statistically significant differences among the three groups, except in the identification of accelerations (Pa = 0.89, 95% CI: 0.83,0.95; Pa = 0.50, 95% CI: 0.41,0.60, and Pa = 0.35, 95% CI: 0.25,0.43 in junior, medium and senior groups, respectively) and the prediction of neonatal acidemia (Pa = 0.52, 0.52, and 0.62 in junior, medium and senior groups, respectively), where agreement was highest and lowest in the junior-level group, respectively. The accuracy and sensitivity of the prediction for umbilical artery pH < 7.1 were similar among the three groups, but the specificity was higher in the senior groups (93.68% vs. 92.53% vs. 98.85% in junior, medium and senior groups, P = 0.015). Conclusion: Although we found a good inter-observer agreement in the evaluation of the most basic CTG features and FHR category statistically, it was insufficient to meet the clinical requirements for “no objection” interpretation for FHR tracings. Further specialized training is needed for standardized interpretation of intrapartum FHR tracings.

Incidence, Intrapartum Risk Factors, and Prognosis of Neonatal Hypoxic-Ischemic Encephalopathy Among Infants Born at 35 Weeks Gestation or More.

Neonatal hypoxic-ischemic encephalopathy (HIE) is associated with neonatal mortality, acute neurological injury, and long-term neurodevelopmental disabilities; however, the association between intrapartum factors and HIE remains unclear. This population-based cohort study used linked obstetrical and newborn data derived from the Nova Scotia Atlee Perinatal Database (NSAPD, 1988-2015) and the AC Allen Perinatal Follow-Up Program Database (2006-2015) for all pregnancies with live, non-anomalous newborns ≥35 weeks gestation, not delivered by pre-labour cesarean section. Temporal trends in HIE incidence were described, and logistic regression estimated odds ratios (OR) with 95% confidence intervals (CI) for the association of intrapartum factors with HIE. The NSAPD identified 227 HIE cases in the population of 226 711 deliveries from 1988 to 2015. Women with clinical chorioamnionitis in labour (OR 8.0; 95% CI 3.9-16), emergency cesarean delivery (OR 10; 95% CI 7.6-14), shoulder dystocia (OR 3.5; 95% CI 2.1-5.7), placental abruption (OR 18; 95% CI 11-29), and cord prolapse (OR 30; 95% CI 15-61) were more likely to have newborns with HIE. Two-thirds of newborns with HIE had an abnormal intrapartum fetal heart rate tracing. The mortality rate among infants with HIE was 27% by 3 years of age. Neurodevelopmental outcomes in the surviving infants were normal in 43% and showed severe developmental delay in 40%. Overall, the rate of HIE was low in infants born at ≥35 weeks gestation. The identification of associated intrapartum factors should promote increased surveillance in these clinical situations and emphasize the importance of careful management to optimize newborn outcomes.

Use of artificial intelligence (AI) in the interpretation of intrapartum fetal heart rate (FHR) tracings: a systematic review and meta-analysis.

To determine the degree of inter-rater reliability (IRR) between human and artificial intelligence (AI) interpretation of fetal heart rate tracings (FHR), and to determine whether AI-assisted electronic fetal monitoring interpretation improves neonatal outcomes amongst laboring women. We searched Medline, EMBASE, Google Scholar, Scopus, ISI Web of Science and Cochrane database search, as well as PubMed ( www.pubmed.gov ) and RCT registry ( www.clinicaltrials.gov ) until the end of October 2018 to conduct a systematic review and meta-analysis comparing visual and AI interpretation of EFM in labor. Similarly, we sought out all studies evaluating the IRR between AI and expert interpretation of EFM. Weighed mean Cohen's Kappa was calculated to assess the global IRR. Risk of bias was assessed using the Cochrane Handbook for Systematic Reviews of Interventions. We used relative risks (RR) and a random effects (RE) model to calculate weighted estimates. Statistical homogeneity was checked by the χ2 test and I2 using Review Manager 5.3.5 (The Cochrane Collaboration, 2014.) We obtained 201 records, of which 9 met inclusion criteria. Three RCT's were used to compare the neonatal outcomes and 6 cohort studies were used to establish the degree of IRR between both approaches of EFM evaluation. With regards to the neonatal outcomes, a total of 55,064 patients were included in the analysis. Relative to the use of clinical (visual) evaluation of the FHR, the use of AI did not change the incidence rates of neonatal acidosis, cord pH below < 7.20, 5-min APGAR scores < 7, mode of delivery, NICU admission, neonatal seizures, or perinatal death. With regards to the degrees of inter-rater reliability, a weighed mean Cohen's Kappa of 0.49 [0.32-0.66] indicates moderate agreement between expert observers and computerized systems. The use of AI and computer analysis for the interpretation of EFM during labor does not improve neonatal outcomes. Inter-rater reliability between experts and computer systems is moderate at best. Future studies should aim at further elucidating these findings.

The relationship between intrapartum fetal heart rate tracings and early neonatal outcomes

The relationship between intrapartum fetal heart rate tracings and early neonatal outcomes

Entropy and Compression Capture Different Complexity Features: The Case of Fetal Heart Rate

Entropy and compression have been used to distinguish fetuses at risk of hypoxia from their healthy counterparts through the analysis of Fetal Heart Rate (FHR). Low correlation that was observed between these two approaches suggests that they capture different complexity features. This study aims at characterizing the complexity of FHR features captured by entropy and compression, using as reference international guidelines. Single and multi-scale approaches were considered in the computation of entropy and compression. The following physiologic-based features were considered: FHR baseline; percentage of abnormal long (%abLTV) and short (%abSTV) term variability; average short term variability; and, number of acceleration and decelerations. All of the features were computed on a set of 68 intrapartum FHR tracings, divided as normal, mildly, and moderately-severely acidemic born fetuses. The correlation between entropy/compression features and the physiologic-based features was assessed. There were correlations between compressions and accelerations and decelerations, but neither accelerations nor decelerations were significantly correlated with entropies. The %abSTV was significantly correlated with entropies (ranging between −0.54 and −0.62), and to a higher extent with compression (ranging between −0.80 and −0.94). Distinction between groups was clearer in the lower scales using entropy and in the higher scales using compression. Entropy and compression are complementary complexity measures.

Perinatal Outcomes Associated With Isolated Velamentous Cord Insertion in Singleton and Twin Pregnancies.

To evaluate perinatal outcomes in singleton and twin pregnancies with pathologically confirmed velamentous cord insertion without vasa previa. This retrospective case-control study included all nonanomalous singleton and twin pregnancies with pathologically confirmed velamentous cord insertion delivered in a single institution between January 1, 2005, and July 1, 2015, and having an ultrasound examination by maternal-fetal medicine. For each case, the next 2 consecutive deliveries matched for gestational age at delivery ± 1 week and, in twins, amnionicity and chorionicity served as controls. Primary outcomes included surgical delivery for a nonreassuring intrapartum fetal heart rate tracing, umbilical arterial cord pH of less than 7.2, 5-minute Apgar score of less than 7, birth weight below the 10th percentile, neonatal intensive care unit admission, fetal or neonatal death, and cord avulsion necessitating manual placental extraction. Outcomes were available for 53 singletons with 103 matched controls and 33 twin pregnancies with 65 matched controls. In singletons, velamentous cord insertion was associated with cord pH of less than 7.2 (odds ratio [OR] 3.5; 95% confidence interval [CI], 1.1-11.2; P = .039), 5-minute Apgar score of less than 7 (OR, 5.3; 95% CI, 0.99-28.1; P = .045), and cord avulsion requiring manual placental extraction (7.5% versus 0%; P = .012). Associations were suggested with increased surgical delivery for a nonreassuring intrapartum fetal heart rate tracing (OR, 2.4; 95% CI, 0.9-6.9; P = .14), birth weight below the 10th percentile (OR, 2.1; 95% CI, 0.8-5.9; P = .21), and fetal or neonatal death (3.8% versus 0%; P = .11). Velamentous cord insertions were also associated with placental abruption in singletons (7.5% versus 0%; P = .013). Among twins, velamentous cord insertion was associated with fetal or neonatal death (9.1% versus 0%; P = .036). Isolated confirmed velamentous cord insertion is associated with adverse perinatal outcomes in singleton and twin gestations.

92: The effect of hindsight and outcome bias on the interpretation and management of intrapartum fetal heart rate (FHR) tracings: A randomized trial

To determine whether obstetricians who are asked to evaluate management decisions regarding abnormal FHR patterns will be more likely to assess the quality of medical care as negligent if they are told that there was an adverse, rather than normal, neonatal outcome. Obstetricians from four institutions were invited to participate in a research study regarding intrapartum management. Each case included clinical details, segments of the intrapartum FHR tracing, and outcomes including umbilical artery pH and presence or absence of neonatal morbidity (Table 1). Reviewers were asked to categorize the FHR tracing, assess the timing for the decision for cesarean delivery (CD), and finally rate the quality of care as either “below standard of care” or “acceptable practice.” All participants received the same clinical data and outcomes for both Case #1 and Case #2. Case #1 involved a scenario with a normal umbilical pH, whereas case #2 resulted in an abnormal umbilical pH (< 7.00). For Case #3, all participants received the same opening clinical vignette and FHR tracings; but then were randomly allocated to receive one of two alternative outcomes (Scenario A = normal umbilical pH and no neonatal complications or Scenario B = metabolic acidemia and neonatal encephalopathy). We estimated that N= 84 would be needed to show a 30% difference in the frequency of the judgment of obstetrical management as “below standard of care” between those receiving alternative outcomes (90% power and 2-sided alpha = 0.05). A total of 128 obstetricians participated; 70 were randomly allocated to Scenario A and 58 to Scenario B for Case #3. There were no differences in the assessment of the appropriateness and quality of care for the first 2 cases (Table 2). For Case #3, belief that there was an adverse outcome resulted in a worse categorization of the FHR tracing, more frequent perception that CD was performed too late, and more likely judgment that the standard of care had been violated (Table 2). The findings were similar regardless of academic institution, attending or trainee status, or MFM subspecialty. This study confirms the significant impact of hindsight and outcome bias on the interpretation of FHR tracings and the retrospective assessment of the quality of obstetrical care.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Interobserver reliability to interpret intrapartum electronic fetal heart rate monitoring: Does a standardized algorithm improve agreement among clinicians?

Our aim was to investigate the accuracy in predicting intrapartum fetal acidaemia and the interobserver reproducibility of a mathematical algorithm for the interpretation of electronic fetal heart rate (FHR) monitoring throughout labour. Eight physicians (blinded to the clinical outcomes of the deliveries) evaluated four randomly selected intrapartum FHR tracings by common visual interpretation, trying to predict umbilical artery base excess at birth. They subsequently were asked to re-evaluate the tracings using a mathematical algorithm for FHR tracing interpretation. Common visual interpretation allowed a correct estimation of the umbilical artery base excess in 34.4% of cases, with a poor interobserver reproducibility (Kappa correlation coefficient = 0.24). After implementation of the algorithm, the proportion of correct estimates significantly increased to 90.6% (p < 0.001), with excellent inter-clinician agreement (κ: 0.85). To conclude, incorporation of a standardised algorithm reduces the interobserver variability and allows a better estimation of fetal acidaemia at birth.

Safe Prevention of the Primary Cesarean Delivery

Safe Prevention of the Primary Cesarean Delivery

Intrapartum fetal heart rate monitoring: evaluation of a standardized system of interpretation for prediction of metabolic acidosis at delivery and neonatal neurological morbidity

Objective: To assess the ability of the intrapartum fetal heart rate interpretation system developed in 2008 by the National Institute of Child Health and Human Development (NICHD) to predict fetal metabolic acidosis at delivery and neonatal neurological morbidity.Methods: We analyzed the intrapartum fetal heart rate tracings of 314 singleton fetuses at ≥37 weeks using the NICHD three-tier system of interpretation: Category I (normal), Category II (indeterminate) and Category III (abnormal). Category II was further divided into Category IIA, with moderate fetal heart rate variability or accelerations, and Category IIB, with minimal/absent fetal heart rate variability and no accelerations. The presence and duration of the different patterns were compared with several clinical neonatal outcomes and with umbilical artery acid-base balance at birth.Results: The mean values of pH and base excess decreased proportionally as tracings worsened (p < 0.001). The duration of at least 30 min for Category III tracings was highly predictive of a pH <7.00 and a base excess ≤−12 mmol/L. The same was true for the duration of Category IIB tracings that lasted for at least 50 min.Conclusions: Our study demonstrates that the interpretation of fetal heart rate tracings based on a strictly standardized system is closely associated with umbilical artery acid-base status at delivery.

Interobserver Reliability of Fetal Heart Rate Pattern Interpretation Using NICHD Definitions

To evaluate the interobserver reliability of fetal heart rate (FHR) pattern definition and interpretation assessed by physicians at various levels of training using standard Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) definitions and standard principles of interpretation. We conducted an interrater reliability study of the intrapartum FHR tracings of 32 singleton term pregnancies at Los Angeles County-University of Southern California (LAC + USC) Medical Center. Analysis included the 5 hours immediately preceding delivery, divided into 10- minute segments. A medical student, resident, and three attending physicians evaluated the same set of FHR tracings. Interobserver agreement was assessed using the free-marginal kappa coefficient. Reviewers demonstrated substantial to excellent agreement on baseline rate (κ = 0.97), moderate variability (κ = 0.80), accelerations (κ = 0.62), decelerations (κ = 0.63), category (κ = 0.68), and the ability to identify the presence of either moderate variability or accelerations (κ = 0.82). Interobserver agreement was significantly higher on all components of FHR definition and interpretation than previously expected. Standardization of FHR definitions and interpretation may improve interobserver reliability and patient safety.

Prediction of fetal base excess values at birth using an algorithm to interpret fetal heart rate tracings: a retrospective validation

To evaluate whether a standardised algorithm to interpret fetal heart rate (FHR) tracings during the entire length of labour can predict umbilical artery base excess at birth, and to investigate its inter- and intra-observer reproducibility. Retrospective study. Obstetrics and gynaecology department at a tertiary referral centre in a university hospital. Group 1: 152 consecutive, generally low-risk, labouring women. Group 2: mixed group of 30 women who delivered a fetus with pH < 7.00 and 30 women who delivered a fetus with pH ≥ 7.00. Intrapartum FHR tracings were retrospectively and blindly evaluated by two independent assessors using an algorithm proposed by Ross and Gala to predict fetal base excess at birth. The accuracy in predicting the base excess values of newborns was expressed as the proportion of FHR tracings in which the operator was able to correctly calculate the actual base excess at birth (approximation of ± 2 mmol/l). Inter- and intra-observer reproducibility were estimated using the Pearson correlation coefficient. In the group of 152 low-risk labouring women, the two assessors correctly predicted the umbilical artery base excess in 73.1 and 76.3% of cases, respectively. Inter-observer (Pearson correlation coefficient = 0.75) and intra-observer (Pearson correlation coefficient = 0.80 and 0.82 for the first and second assessor, respectively) reproducibility was very good. In the 30 fetuses that were acidemic, the first and second observers correctly predicted base excess values in 23 (76.7%) and 21 (70%) cases, respectively (inter-observer reproducibility, Pearson correlation coefficient = 0.72). The algorithm proposed by Ross and Gala may be a valuable tool to estimate changes in umbilical base excess during active labour, with a high inter- and intra-observer reproducibility.

Electronic Fetal Heart Rate Monitoring

Electronic fetal heart rate monitoring (EFM) continues to be the primary method utilized for fetal assessment in the United States. Standardization of nomenclature associated with this perinatal technology has evolved over the past 40 years such that the current nomenclature recommended by the National Institute of Child Health and Human Development (NICHD) has been adopted by professional perinatal organizations as the agreed-upon method for professional communication and documentation. Current research continues to focus on the optimal management of intrapartum fetal heart rate tracings. The clinical controversies and challenges related to electronic fetal heart rate monitoring continue to evolve.

Association between intrapartum fetal heart rate patterns and neonatal abstinence syndrome in methadone exposed neonates

Objective. Determine whether infants exposed to chronic maternal methadone with abnormal intrapartum fetal heart rate (FHR) patterns are more likely to require treatment for neonatal abstinence syndrome (NAS).Study design. Intrapartum FHR tracings analyzed in 104 pregnancies at ≥34 weeks gestation for FHR variability, accelerations, and decelerations. FHR patterns compared between neonates based on treatment with methadone for NAS. Secondary analysis included relation between maternal methadone dose and intrapartum FHR patterns, initiation of methadone, age at methadone initiation, and total neonatal methadone dose. Study powered to detect 30% increase in NAS incidence in neonates with abnormal FHR tracings.Results. Seventy-six (73%) of 104 neonates required methadone treatment for NAS. Neonates who required methadone had higher average baseline FHR (131 vs. 126 bpm; p < 0.04) in active labor and less likely to have FHR tracings without accelerations (1.7% vs. 20.3%; p = 0.007) in latent labor. No significant associations between neonate's need for methadone and intrapartum FHR variability or FHR decelerations. No association between maternal methadone dose (range 30–280 mg) and treatment for NAS.Conclusion. The need for an infant to require methadone treatment for NAS was not reliably predicted by the intrapartum FHR patterns or the maternal methadone dose.

Fetal heart rate pattern notification guidelines and suggested management algorithm for intrapartum electronic fetal heart rate monitoring.

Numerous randomized controlled trials have demonstrated limited efficacy of intrapartum fetal heart rate monitoring in improving fetal outcome. A potential reason is the wide variability in clinical decision making seen with its use. Standardizing management of variant intrapartum fetal heart rate tracings may reduce this variability and lead to improvement in fetal outcome. We sought to develop notification guidelines and a management algorithm for variant intrapartum fetal heart rate tracings that improve fetal outcome and do not increase the operative delivery rate. Outcomes for cases involving the use of our notification guidelines and management algorithm over six months (1181 deliveries) were compared with outcomes for historical control subjects (2247 deliveries). The main outcome measures were Apgar scores <7 and the operative delivery rate. We found no change in fetal outcome or operative delivery rate. Our notification guidelines and management algorithm are safe and do not increase the operative delivery rate. A large multicenter trial is needed to demonstrate improvement in fetal outcome.

Effect of Chronic Maternal Methadone Therapy on Intrapartum Fetal Heart Rate Patterns

Treatment of maternal opioid dependence with methadone is associated with a delay in fetal heart rate (FHR) accelerations in nonstress tests. The objective of this investigation was to determine the effect of methadone maintenance therapy on intrapartum FHR patterns. This retrospective cohort study compared intrapartum FHR tracings from 56 methadone-treated patients > or =36 weeks gestation with a control group of nonsubstance using patients matched for maternal age, parity, gestational age, and ethnicity. Blinded FHR interpretation included the recording of baseline, variability, accelerations, and late or severe variable decelerations. The 8-point FHR scoring system was based on the National Institute of Child Health and Human Development Research Planning Workshop guidelines. We considered a 25% reduction in the score during the latent phase to be significant. The median maintenance dose of methadone was 70 mg daily, with a range between 20 mg and 130 mg. Each patient tested negative for other substances on urine screening before admission. The significantly lower FHR score in the methadone group (mean difference, 1.4; 95% confidence interval, 1.1 to 1.7) was attributed to a lower baseline (P <.05), less moderate or marked variability (P <.01), and a lower proportion of accelerations during the first stage of labor (P <.01). A higher proportion of methadone-exposed fetuses had late or severe variable decelerations in the second stage (44.2% vs 22.9%; P <.03). Analgesic needs, operative vaginal or cesarean delivery rates, and Apgar scores less than 7 at 1 and 5 minutes were not significantly different between the two groups. Chronic maternal methadone treatment affects intrapartum FHR patterns by reducing the variability, baseline, and proportion of accelerations during the first stage. These subtle drug-induced effects do not compromise intrapartum decision-making or immediate newborn adjustments.

Comparison of intrapartum fetal heart rate tracings in patients with neonatal seizures vs. no seizures: what are the differences?

To determine which intrapartum fetal heart rate parameters in the presence of severe neonatal acidosis (pH < 7.0) appropriately predicts the development of neonatal seizures in the context of hypoxic ischemic encephalopathy (HIE). The intrapartum fetal heart rate tracings of 25 neonates who developed neonatal seizures secondary to HIE were compared with 25 matched neonates with similar pH and gestational age who did not develop seizures. All patients had at least 2 hours of intrapartum fetal heart rate patterns available for review. We compared the fetal heart rate parameters of prolonged deceleration, variable and late decelerations, variability, accelerations, fetal heart rate baseline and duration of the fetal heart rate abnormality. Comparison between the groups was done using chi-square for nominal data and student t-tests for continuous data. Neonates with seizures 2 degrees HIE had a significantly longer duration of abnormal fetal heart rate patterns (72 +/- 12 minutes vs 48 +/- 12 minutes, p < 0.001). This study demonstrated that in the setting of neonatal acidosis the development of seizures is related to the period of stress (duration of the abnormal fetal heart rate pattern).

Resident evaluation of intrapartum fetal heart-rate tracings: can they predict acidosis?

Resident evaluation of intrapartum fetal heart-rate tracings: can they predict acidosis?

Fetal heart rate parameters predictive of neonatal outcome in the presence of a prolonged deceleration

OBJECTIVE: To correlate the presence of baseline variability and the duration of a prolonged deceleration/bradycardia in intrapartum fetal heart rate (FHR) tracings with the development of neonatal acidemia. METHODS: We identified 186 patients with term gestations who had continuous electronic fetal monitoring for at least 2 hours before delivery, with an identified bradycardia during that period. Each patient had umbilical artery cord analysis done and delivery within 30 minutes of that bradycardia. One investigator blinded to the cord gas outcome reviewed the last 2 hours of the tracing using the National Institute of Child Health and Human Development guidelines for FHR monitoring. We assessed the presence or absence of variability before the bradycardia and recovery or no recovery of the bradycardia and placed the patients into four groups. Group 1 (128 patients) with normal variability and recovery, group 2 (40 patients) with normal variability and no recovery, group 3 (nine patients) with decreased variability and recovery, and group 4 (nine patients) with decreased variability and no recovery. We compared the incidence of neonatal acidosis defined as a pH of less than 7.0 at birth among the four groups. The relationship between the various groups was assessed using analysis of variance and the χ 2 test. In addition, a multiple logistic regression model was developed with the parameters of amplitude and recovery used to predict pH at birth. RESULTS: The presence of decreased variability and no recovery of the FHR of a bradycardia was associated with the lowest pH 6.83 ± 0.16 and a 78% incidence of significant acidosis. Decreased variability before FHR bradycardia was the FHR parameter significantly correlated with low pH. CONCLUSION: The most significant factor predicting the development of pathologic neonatal acidemia and indicating the need for urgent delivery in the presence of a bradycardia is decreased variability before the bradycardia.

182 C/section as an appropriate intervention for abnormal intrapartum fetal heart rate tracings

182 C/section as an appropriate intervention for abnormal intrapartum fetal heart rate tracings