Optimal Interval Between Prostaglandin E₂ Ripening of the Cervix and Oxytocin Induction of Labor: A Prospective Clinical Trial

Abstract

Does altering the interval between prostaglandin E₂ (PGE) gel application and oxytocin administration shorten induced labor without loss in efficacy? A prospective clinical trial was completed for 133 clinic patients who were candidates for the induction of labor with an unfavorable cervical status. All patients were randomly allocated to receive intracervical PGE gel 0.5 mg either 6 h or 1 h prior to the standardized administration of oxytocin. Repeat gel application and serial-day induction were offered to those judged medically stable who continued to meet inclusion criteria.

The gel to delivery duration was significantly shortened when comparing the 6-h interval to the 12-h interval only among single-day induction patients (P = 0.004) and was associated with a nonsignificant trend toward higher rates of failed induction and cesarean delivery (P = 0.073). When all patients are included, no difference between the groups was observed in the progress or outcome of labor.

A 6-h interval between PGE and oxytocin will shorten the interval to vaginal delivery only when labor is limited to a single-day attempt, but with a probable increased risk of failed induction and cesarean delivery.

Key Words:

• Labor induction
• Prostaglandin E₂
• Cervical ripening
• Uterine rupture