Amniotomy for shortening spontaneous labour

Intentional artificial rupture of the amniotic membranes during labor, sometimes called amniotomy or "breaking of the waters," is one of the most commonly performed procedures in modern obstetric and midwifery practice. The primary aim of amniotomy is to speed up contractions and, therefore, shorten the length of labor. However, there are concerns regarding unintended adverse effects on the woman and infant.

To determine the effectiveness and safety of amniotomy alone for 1) routinely shortening all labors that start spontaneously and 2) shortening labors that have started spontaneously but have become prolonged.

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 30, 2007).

Randomized controlled trials comparing amniotomy alone with intention to preserve the membranes. We excluded quasi-randomized trials.

Two authors assessed identified studies for inclusion. Both authors extracted data. Primary analysis was by intention to treat.

We have included 14 studies in this review, involving 4,893 women. There was no evidence of any statistical difference in length of first stage of labor (weighted mean difference -20.43 minutes, 95% confidence interval [CI] -95.93 to 55.06), maternal satisfaction with childbirth experience (standardized mean difference 0.27, 95% CI -0.49 to 1.04), or low Apgar score less than seven at 5 minutes (relative risk 0.55, 95% CI 0.29 to 1.05). Amniotomy was associated with an increased risk of cesarean delivery compared with women in the control group, although the difference was not statistically significant (RR 1.26, 95% CI 0.98 to 1.62). There was no consistency between papers regarding the timing of amniotomy during labor in terms of cervical dilatation.

On the basis of the findings of this review, we cannot recommend that amniotomy be introduced routinely as part of standard labor management and care. We do recommend that the evidence presented in this review be made available to women offered an amniotomy and suggest that it may be useful as a foundation for discussion and any resulting decisions made between women and their caregivers.