Objective: To determine the influence of a training course in physiology-based interpretation of cardiotocography (CTG) on professional practices. Design: A cross-sectional study. Setting: A national online survey. Population: Fifty-seven French obstetricians Methods: The participants were divided into two groups: the training group (obstetricians who had already participated in a training course in physiology-based interpretation of CTG) and the control group. Ten medical records of patients who had abnormal CTG tracings and underwent a foetal scalp blood sampling (pH) during labour were presented to the participants. They were given three choices: (i) use a second-line method, (ii) continue labour without using a second-line method, or (iii) perform a caesarean section. Main outcome measures: Median number of decisions to use second-line methods. Results: Forty participants were included in the training group and 17 in the control group. The median number of recourses to a second-line method was significantly inferior for the training group (4 [2–6] second-line methods on 10 records) than for the control group (6 [4–7]; p = 0.040). Regarding the 4 records for which a caesarean section was the real outcome, the median number of decisions of continuing labour was significantly superior in the training group than in the control group (1 [0–1] vs. 0 [0–1]; p = 0.032). Conclusions: Participation in a training course in physiology-based interpretation of CTG could be associated with a less frequent use of second-line methods. Additional studies are required to determine whether this change in attitude is safe for the foetal well-being.