NICE 2017 intrapartum fetal CTG interpretation guidelines- Examining its reliability among clinicians: A prospective observational study

Objective: Evaluation of the inter-observer and intra-observer agreement for CTG interpretation by NICE guidelines 2017. Design: A hospital-based Prospective observational study. Setting: The study was conducted at a university teaching hospital Sample size: A total of 165 CTG tracings from 165 laboring women were included in the study for interpretation by 6 clinicians with varying levels of experience in the specialty. Methods: 6 clinicians (3 consultants & 3 residents in training) independently interpreted CTG traces using NICE 2017 guidelines twice with a locking period of 3 months between 2 interpretations. Main outcome measure: Fleiss’s kappa and Cohen’s kappa coefficient was employed for ascertaining interobserver and intraobserver agreement using SPSS statistical software. Results: Among all CTG parameters, observed agreement for baseline fetal heart was substantial [k=0.678(0.677-0.679), p<0.0001] but the congruence for variability was only slightly above the chance [0.185 (0.184-0.186), p<0.0001]. Overall kappa coefficient was 0.382 (0.381-0.383) with a p<0.0001 (moderate agreement) for classifying the CTG category. The intra-observer agreement of most senior consultant for baseline was nearly perfect (Kf=0.937) as compared to a kappa coefficient of 0.367 of the junior-most resident. Conclusions: Different CTG interpretation parameters were observed to have varying levels of agreement among clinicians. Where experience was witnessed to improve the agreement, the higher degree of non-congruence in certain CTG parameters like variability, and type of decelerations may perhaps point to the need for further objectivity in defining these parameters.