Objective To quantify the incidence of intrapartum risk factors in labours with an adverse outcome, and compare them with the incidence of the same indicators in a series of consecutive labours without adverse outcome. Design Case–control study. Setting Twenty‐six maternity units in the UK. Population or sample Sixty‐nine labours with an adverse outcome and 198 labours without adverse outcome. Methods Observational study. Main outcome measures Incidence of risk factors in hourly assessments for 7 hours before birth in the two groups. Results A risk score combining suspected fetal growth restriction, tachysystole, meconium in the amniotic fluid and fetal heart rate abnormalities (baseline rate and variability, presence of decelerations) gave the best indication of likely outcome group. Conclusions Accurate risk assessment in labour requires fetal heart rate abnormalities to be considered in context with additional intrapartum risk factors.