Thesis (M.Med.(Obstetrics and Gynaecology))--University of the Witwatersrand, Faculty of Health Sciences, 2015Objective: To assess consensus in the interpretation of cardiotocographs (CTGs) and non-stress
tests (NSTs) between different grades of obstetric clinical staff by comparing assessment of
traces by non-systematic eyeballing with assessment of traces using a tabular approach suggested
by the National Institute of Health and Clinical Excellence (NICE) guidelines for interpretation
of CTGs and NSTs, and to identify components ofNSTs and CTGs where medical personnel
experience difficulty with interpretation.
Design: Prospective observational study.
Setting: Maternity units of the tertiary care hospitals for the teaching and training of the
Witwatersrand University postgraduates, interns and midwives.
Participants: Midwives, advanced midwives, interns, medical officers, registrars and specialists
working in the above-mentioned maternity units.
Method: Participants were recruited at the time of formal gatherings and departmental meetings
in the various institutions. Each participant was given five traces that were a combination of
NSTs and CTGs to interpret and assess in a non-systematic way using three categories: baby
well; baby requires further surveillance; and baby needs immediate delivery. The same
participants were then given the same set of traces in a different sequence for interpreting in a
systematic way using the tabular approach from the NICE guidelines on electronic fetal
monitoring with a scoring modification.
Main outcome measure: Differences in interpretation of CTGs by different grades of staff, and
degree of certainty between study participants in the different assessment systems.
Results: Twenty seven specialists, 25 registrars, 21 medical officers, 10 interns and 15 midwives
participated. There were varying interpretations by individuals in both the non-systematic
assessment and the systematic assessment using the NICE tabular application, with best
agreement in Trace 3 (77% and 84% respectively). In the non-systematic assessment, there was a
statistically significant difference in the assessment of traces 1, 2 and 4 between the different
grades of staff(P-values<0.01, 0.03 and <0.01 respectively). There was no statistically
significant difference when the traces were assessed using the NICE guidelines tabular
application (P-values; Trace1 >0.99, Trace2=0.27, Trace 3 = 0.76, Trace 4 = 0.15 and Trace5 =
0.35).Certainty of the evaluation by the participants was determined if75% or more of the
participants agreed on a classification. Using the NICE guidelines, there was uncertainty (failure
to agree on classification by 75% or more of the participants) with baseline variability,
accelerations, decelerations and overall assessment of the CTG in most of the traces.
Conclusion: There is no uniformity in the assessment of traces by midwives, interns, medical
officers, registrars and specialists. Some uniformity in the interpretation of traces and reduction
in inter-observer variation is attained by the use of the NICE guidelines tabular application.
However, baseline variability, accelerations, and decelerations remain a problem in the
interpretation of NSTs and CTGs using the NICE guidelines
