A systematic review included 15 studies involving a total of 5 583 women. Between women in the amniotomy and no amniotomy (control groups), there was no clear statistical difference in length of first stage of labour (weighted mean difference -20.43 minutes, 95% CI -95.93 to 55.06, 5 trials, n=1127), caesarean section (RR 1.27, 95% CI 0.99 to 1.63; 9 trials, n=5 021), maternal satisfaction with childbirth experience or low Apgar score less than 7 at five minutes (RR 0.53, 95% CI 0.28 to 1.00, 6 trials, n=3 598). . There was no consistency between papers regarding the timing of amniotomy during labour in terms of cervical dilatation. Between amniotomy alone versus intention to preserve the membranes (no amniotomy) for spontaneous labours that have become prolonged, there was no clear statistically significant difference in one study (n=39) in caesarean section (RR 0.95, 95% CI 0.15 to 6.08), maternal satisfaction with childbirth experience (MD 22.00, 95% CI 2.74 to 41.26) or Apgar score less than seven at five minutes (RR 2.86, 95% CI 0.12 to 66.11).
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in interventions and outcomes) and by indirectness (differences between the inclusion criteria pertaining to the cervical dilatation).