Objective: To obtain estimates of the effects of amniotomy on the risk of cesarean delivery and on other indicators of maternal and neonatal morbidity (Apgar score less than 7 at 5 minutes, admission to neonatal intensive care unit [NICU]).
Data sources: Published studies were identified through manual and computerized searches using Medline and the Cochrane Collaboration Pregnancy and Childbirth Database.
Methods of study selection: Our search identified ten trials, all published in peer-reviewed journals. Trials were assigned a methodological quality score based on a standardized rating system. Three trials were excluded from the analysis for methodological limitations.
Tabulation, integration, and results: Data were abstracted by two trained reviewers. Typical odds ratios (OR) were calculated. Amniotomy was associated with a reduction in labor duration varying from 0.8-2.3 hours. There was a nonstatistically significant increase in the risk of cesarean delivery; OR 1.2, 95% confidence interval (CI) 0.9-1.6. The risk of a 5-minute Apgar score less than 7 was reduced in association with early amniotomy (OR 0.5, 95% CI 0.3-0.9). Groups were similar with respect to other indicators of neonatal status (arterial cord pH, NICU admissions).
Conclusion: Routine early amniotomy is associated with both benefits and risks. Benefits include a reduction in labor duration and a possible reduction in abnormal 5-minute Apgar scores. This meta-analysis provides no support for the hypothesis that routine early amniotomy reduces the risk of cesarean delivery. An association between early amniotomy and cesarean delivery for fetal distress was noted in one large trial, suggesting that amniotomy should be reserved for patients with abnormal labor progress.