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

OBJECTIVES: To determine the efficacy and safety of a 2-tier, Bishop score-driven induction schedule using gel and tablet formulations of PGE2 to establish new monitoring guidelines. DESIGN: Prospective descriptive study. SETTING: eight Germany 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 < 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.