The labour progression study (LaPS): duration of labour following zhangs's guideline and the who partograph - A cluster randomised trial

Introduction and aim: Traditionally, the progress of labour is measured by cervical dilatation. However, the expected progression varies between countries and there is no consensus regarding which guideline is best suited for clinical use. The applicability of stages, phases and time limits in labour is challenging, mainly because of variations in defining the onset of labour and transition of phases and stages. One concern is that women may undergo unnecessary interventions because slow progress of labour is poorly defined. Therefore, understanding the normal variations of duration of labour is of great importance and should be the basis for identifying the actual slow progress of labour, which requires interventions. The purpose of present study was to investigate labour duration in different phases of labour when adhering to Zhang's guideline for labour progression compared with the WHO partograph. Method: This is a cluster randomized controlled trial in 14 birth care units in Norway, randomly assigned to either the intervention group, which followed Zhang’s guideline, or to the control group, which followed the WHO partograph, for labor progression. 7277 nulliparous women with singleton foetus in a cephalic presentation and spontaneous onset of labour at term were included. Results: The adjusted median duration of labour was 7.0 h in the Zhang group, compared with 6.2 h in the WHO group; the median difference was 0.84 h with 95% confidence interval [CI] (0.2-1.5). The adjusted median duration of the first stage was 5.6 h in the Zhang group compared with 4.9 h in the WHO group; the median difference was 0.66 h with 95% CI (0.1-1.2). The corresponding adjusted median duration of the second stage was 88 and 77 min; the median difference was 0.18 h with 95% CI (0.1-0.3). Conclusion: We observed statistical significant differences in the duration of labour between the compared groups.