Agreement and accuracy using the FIGO, ACOG and NICE cardiotocography interpretation 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.