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Agreement and accuracy using the FIGO, ACOG and NICE cardiotocography interpretation guidelines
Susana Santo1, Diogo Ayres-de-Campos2, Cristina Costa-Santos3
1Department of Obstetrics and Gynecology, Santa Maria Hospital, Faculty of Medicine of Lisbon University, Lisbon, Portugal.
Insights
Cardiotocography interpretation agreement varies between guidelines. The International Federation of Gynecology and Obstetrics and National Institute for Health and Care Excellence guidelines showed better reliability and sensitivity for predicting newborn acidemia compared to the American College of Obstetrics and Gynecology guidelines.
Area of Science:
- Obstetrics and Gynecology
- Fetal Monitoring
- Neonatal Health
Background:
- Cardiotocography (CTG) interpretation suffers from modest interobserver agreement, impacting clinical decision-making.
- Standardized guidelines aim to improve CTG analysis consistency.
- Comparing different guideline interpretations is crucial for optimizing fetal surveillance.
Purpose of the Study:
- To compare the agreement, reliability, and accuracy of CTG interpretation across three major guidelines: International Federation of Gynecology and Obstetrics (FIGO), American College of Obstetrics and Gynecology (ACOG), and National Institute for Health and Care Excellence (NICE).
- To assess the predictive value of each guideline's classification for newborn acidemia.
Main Methods:
- 151 CTG tracings were independently interpreted by 27 clinicians across three centers.
- Interobserver agreement was quantified using proportion of agreement and reliability (κ statistic).
- Accuracy in predicting newborn acidemia was evaluated for pathological (Category III) tracings, with 95% confidence intervals calculated.
Main Results:
- CTG classifications were more evenly distributed using FIGO and NICE guidelines compared to ACOG.
- ACOG Category II showed the highest agreement (0.73), while ACOG Categories I and III had the lowest.
- Reliability was slight/fair across all guidelines (κ = 0.15 for ACOG, 0.37 for FIGO, 0.33 for NICE).
- FIGO and NICE demonstrated higher sensitivity for predicting acidemia (89% and 97%) versus ACOG (32%), while ACOG achieved higher specificity (95%).
Conclusions:
- ACOG guidelines yield high agreement for Category II but exhibit low reliability, sensitivity, and high specificity for acidemia prediction.
- FIGO and NICE guidelines offer improved reliability and a trend toward higher sensitivity for acidemia prediction, albeit with lower specificity.
- Guideline choice impacts CTG interpretation consistency and predictive accuracy for adverse neonatal outcomes.
Introduction:
One of the limitations reported with cardiotocography is the modest interobserver agreement observed in tracing interpretation. This study compared agreement, reliability and accuracy of cardiotocography interpretation using the International Federation of Gynecology and Obstetrics, American College of Obstetrics and Gynecology and National Institute for Health and Care Excellence guidelines.
Material And Methods:
A total of 151 tracings were evaluated by 27 clinicians from three centers where International Federation of Gynecology and Obstetrics, American College of Obstetrics and Gynecology and National Institute for Health and Care Excellence guidelines were routinely used. Interobserver agreement was evaluated using the proportions of agreement and reliability with the κ statistic. The accuracy of tracings classified as "pathological/category III" was assessed for prediction of newborn acidemia. For all measures, 95% confidence interval were calculated.
Results:
Cardiotocography classifications were more distributed with International Federation of Gynecology and Obstetrics (9, 52, 39%) and National Institute for Health and Care Excellence (30, 33, 37%) than with American College of Obstetrics and Gynecology (13, 81, 6%). The category with the highest agreement was American College of Obstetrics and Gynecology category II (proportions of agreement = 0.73, 95% confidence interval 0.70-76), and the ones with the lowest agreement were American College of Obstetrics and Gynecology categories I and III. Reliability was significantly higher with International Federation of Gynecology and Obstetrics (κ = 0.37, 95% confidence interval 0.31-0.43), and National Institute for Health and Care Excellence (κ = 0.33, 95% confidence interval 0.28-0.39) than with American College of Obstetrics and Gynecology (κ = 0.15, 95% confidence interval 0.10-0.21); however, all represent only slight/fair reliability. International Federation of Gynecology and Obstetrics and National Institute for Health and Care Excellence showed a trend towards higher sensitivities in prediction of newborn acidemia (89 and 97%, respectively) than American College of Obstetrics and Gynecology (32%), but the latter achieved a significantly higher specificity (95%).
Conclusions:
With American College of Obstetrics and Gynecology guidelines there is high agreement in category II, low reliability, low sensitivity and high specificity in prediction of acidemia. With International Federation of Gynecology and Obstetrics and National Institute for Health and Care Excellence guidelines there is higher reliability, a trend towards higher sensitivity, and lower specificity in prediction of acidemia.
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