Objective To assess the effect of three different partograms on caesarean section and maternal satisfaction.

Design Prospective randomised clinical trial.

Setting Regional teaching hospital in North West of England.

Participants Nine hundred and twenty-eight primigravid women with uncomplicated pregnancies who presented in spontaneous labour at term.

Interventions The women were randomised to have their progress of labour recorded on a partogram with an action line 2, 3 or 4 hours to the right of the alert line. If the progress reached the action line, a diagnosis of prolonged labour was made. Prolonged labour was managed according to the standard ward protocol.

Main outcome measures Primary: Caesarean section rate and maternal satisfaction; secondary: need for augmentation, duration of labour, analgesia, cord blood gas analysis, postpartum haemorrhage, number of vaginal examinations, Apgar score and admission to special care baby unit.

Results Caesarean section rate was lowest when labour was managed using a partogram with a 4-hour action line. The difference between the 3- and 4-hour partograms was statistically significant (OR 1.8,95% CI, but the difference between 2 and 4 hours was not (OR 1.4, 95% CI 0.8-2.4). The women in the 2-hour arm were more satisfied with their labour when compared to the women in the 3-hour (P < 0.0001) and 4-hour (P < 0.0001) arm.

Conclusion Our data suggest that women prefer active management of labour. It is possible that partograms which favour earlier intervention are associated with higher caesarean section rate. As the evidence on which to base the choice of partograms remains inconclusive further satisfaction. research is required.