Objective: To explore the level of agreement as well as the contribution of human-factors on CTG interpretation in a hospital where a high intense, 'fetal physiology-based' training on CTG-interpretation was implemented by a dedicated CTG-Team. Design: Prospective observational study Setting: Tertiary Hospital, UK Population: A total of 25 midwives and 7 doctors ([?]10% of staff) Method: interpretation of 5 anonymised colour-printed copies of 5 different CTGs using a questionnaire (160 CTG interpretations) using local CTG-guidelines (pattern-recognition approach) and Types of hypoxia (fetal-physiology).Results: Interpretation of CTG by type of hypoxia compared against CTG-guidelines presented better Proportion of concordance (PC=76.1% vs 61.2%, P=0.006) and slightly better reliability (K= 0.37 (0.35-0.39) vs 0.33 (0.32-0.36)). Doctors rely most in fetal-physiology than midwives who rely most in guidelines. Overall, 68% of the staff felt confident or very confident in CTG interpretation. In general, Self-reported confidence on CTG interpretation and fetal-physiology knowledge increased with the level of seniority. Conclusions: 'Fetal-physiology-based' training increases level of self-reported confidence and level of fetal-physiology knowledge leading to better inter-observer agreement and reliability in CTG interpretation especially when considering type of hypoxia in CTG-classification. Funding: JG collected the data as part of a Self-funded university MSc program. A secondary analysis of the data was performed to elaborate this manuscript.