Comparison of prostaglandin E2 and intravenous oxytocin for induction of labor.

One hundred nulliparas at term were randomly given oxytocin intravenously or prostaglandin E2 (PGE2) gel (0.5 mg PGE2) intracervically in order to study the effect on cervical ripening and the frequency of successful inductions. In the presence of a favorable cervix both methods seemed equally efficacious in inducing labor. However, when the cervix was unfavorable, 53% of the patients could be delivered with PGE2 gel, compared with 31% when oxytocin was given. In patients with a highly unfavorable cervix this difference was significant (P less than 0.02). In patients not induced into labor, PGE2 gel caused a considerable ripening of the cervix, with a change in Bishop score from 2.9 to 6.3. In patients undelivered after oxytocin stimulation, no change in Bishop score occurred. This effect of locally applied PGE2 gel on cervical ripening was highly significant (P less than 0.001). No adverse maternal or perinatal effects were observed, irrespective of the mode of treatment.