Fetal heart rate tracings: observers versus computer assessment

Abstract

Cardiotocography (CTG) is widely used despite the fact that its diagnostic accuracy is far from satisfying. This is due, among other reasons, to the great intra- and interobserver variation in reading the fetal heart rate tracings. Computerized analysis might be a means to overcome the latter problem.

Objective: the present study was designed to assess the reproducibility of CTG readings among observers and between observers and a computer system.

Study design: 63 fetal heart rate tracings were read by 4 clinicians (2 experienced and 2 inexperienced) and by the 2CTG computerized system. The variables considered were: baseline fetal heart rate (FHR), long-term variability (amplitude bandwidth around the baseline), number of large accelerations and number and type of decelerations.

Results: the agreement among observers, assessed by means of kappa coefficient, ranges from fair to good. The agreement between each of the observers and the computer readings, ranges from 0.18 to 0.48 for FHR baseline, from 0.16 to 0.74 for variability, from 0.37 to 0.64 for the number of accelerations and from 0.41 to 0.54 for the number of decelerations. The agreement on the type of decelerations is very low (0.01-0.25).

Conclusion: it is concluded that interobserver variability between experienced observers, inexperienced observers and 2CTG is considerable and that the use of a computer system should overcome this problem.