"Breaking the water" may not shorten labour

Intentional rupture of the amniotic membranes during labour, causing the release of the amniotic fluid, does not strengthen or accelerate contractions or shorten the length of labour. Although widely practiced, there is little evidence that this procedure, also referred to as amniotomy or "breaking the water", makes any difference in the outcome of labour. Researchers at the University of Liverpool in the UK evaluated the Cochrane Pregnancy and Childbirth Group's Trials Register for clinical trials that randomly assigned patients to amniotomy or regular labour. They identified 14 trials that included 4,893 women. The reviewers noted that these studies had high levels of variation for nearly all of the factors analysed, along with a wide variation in trial eligibility requirements and a lack of information for many variables. It was observed that there were no statistically significant differences between groups in any of the primary outcomes analysed including length of the first stage of labour, maternal satisfaction with the childbirth experience, risk of cesarean section and risk of a low Apgar score at five minutes. However, there was a slightly increased risk of cesarean and a slightly reduced risk of low Apgar score for the group that underwent amniotomy. Amniotomy also had little effect on length of labour, need for pain relief, treatment to induce contractions, maternal bleeding after delivery, infection, or umbilical cord prolapse (a dangerous condition in which the umbilical cord comes out of the birth canal before the infant's head, and can cut off the oxygen supply to the baby). Amniotomy made no differences in infant outcomes, including admission to neonatal intensive care, or complications like meconium aspiration or acidosis. The results suggest that amniotomy should not be introduced routinely as part of standard labour management and care. However, there is a need for additional large, well-designed trials to evaluate the outcome of amniotomies.