"Breaking the water" doesn't speed labor

NEW YORK (Reuters Health) - Intentional rupture of the amniotic membranes during labor, causing the release of the amniotic fluid, does not strengthen or accelerate contractions or shorten the length of labor, according to a review published online in The Cochrane Library.

Although widely practiced, there is little evidence that this procedure, also referred to as amniotomy, makes any difference in the outcome of labor, note Dr. S. Kate Alldred at the University of Liverpool in the UK and colleagues.

The investigators searched the Cochrane Pregnancy and Childbirth Group's Trials Register for clinical trials that randomly assigned patients to amniotomy or regular labor.

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 analyzed, along with a wide variation in trial eligibility requirements and a "disappointing lack of information" for many variables.

Alldred's group observed no statistically significant differences between groups in any of the primary outcomes analyzed including length of the first stage of labor; maternal satisfaction with the childbirth experience; risk of cesarean section; and risk of a low Apgar score at 5 minutes.

However, they did note 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 the length of the second stage of labor; the need for pain relief; treatment to induce contractions; maternal hemorrhaging after delivery; infection; or umbilical cord prolapse, a dangerous condition in which the umbilical cord begins to exit the birth canal before the infant's head does, which can cut off the oxygen supply.

Amniotomy made no differences in infant outcomes, including admission to neonatal intensive care; meconium aspiration; or acidosis.

Alldred and her associates believe there is a need for additional large, well-designed trials to evaluate the outcome of amniotomies, but "on the basis of the findings of this review, we do not recommend that amniotomy be introduced routinely as part of standard labor management and care."

SOURCE: The Cochrane Library, October 17, 2007 online.