Balloon cervical ripening with extra-amniotic infusion of saline or prostaglandin E₂: A double-blind, randomized controlled study

Objective: To compare extra-amniotic infusion of diluted prostaglandin (PG) E₂ solution with saline infusion in balloon cervical ripening and labor induction. Methods: Women with pregnancy complications and Bishop scores of 3 or lower (n = 116) were assigned randomly to receive extra-amniotic infusion (1 mL/minute) of normal saline or PGE₂ in saline (0.5 μg/mL) through a Foley catheter with a 30-mL inflated balloon. We induced labor using intravenous oxytocin only when labor had not developed by 6 hours after balloon expulsion. Analysis was by intent-to-treat. We assessed ripening efficiency and course of labor in women who had spontaneous balloon expulsion (n = 110) and trial of labor (n = 107), respectively. Results: Ripening with PGE₂ was associated with significantly shorter mean (± standard error of the mean [SEM]) time for balloon expulsion (4.7 ± 0.4 versus 6.5 ± 0.6 hours) and with significantly higher Bishop scores (P < .002), compared with ripening with saline. In the PGE₂ group, rates of labor induction (15%) and oxytocin use (37%) were significantly lower than in the saline group (51% and 72%, respectively). The groups did not differ significantly in other labor abnormalities, labor duration, mode of delivery, birth weight, Apgar scores, and puerperal morbidity. Conclusion: Cervical ripening by extra-amniotic balloon and PGE₂ infusion is faster and more effective than by balloon and saline infusion, resulting in a higher rate of spontaneous labor and a lower rate of oxytocin use.