Efficacy and safety of a 2-tier prostaglandin labor induction schedule

Objectives: To determine the efficacy and safety of a 2tier, Bishop score-driven induction schedule using gel and tablet formulations of PGE2 to establish new monitoring guidelines. Design: Prospective descriptive study. Setting: eight German University obstetric departments. Subjects: 467 high risk patients. Interventions: Bishop score < 5: intracervical 0.5 mg PGE2 gel; Bishop score 5-7: intravaginal 3 mg PGE2 tablet. Main outcome measures: Uterine hyperstimulation. < 5 contractions/min, contraction duration < 2 min and emergency tocolytic therapy; perinatal outcome: secondary caesarean section rate, operative vaginal delivery and fetal acidosis. Results: PGE2 induction resulted in spontaneous delivery in 76.9% (6.4% fetal acidosis) and 14.1% secondary c. section. The gel was associated with more adverse uterine effects and a poorer fetal outcome than the tablet. Adverse uterine events increased significantly on repeat dosing with the gel (39.5 vs 29.3%), but not the tablet; they also increased with a dosing interval than 8 h with either formulation. Overall, adverse uterine events were fewer and perinatal outcome better in multiparae than in nulliparae. Conclusions: The higher adverse uterine event rate with the gel should be viewed against the backdrop of the low Bishop score. The interval between repeat dosing should not be less than 8 h after PGE2 gel treatment. Primigravidae must be monitored with special care following labour induction with PGE2.