The objective of this investigation was to compare the efficacy, safety, and cost of intravaginal misoprostol as a labor induction agent to a standard protocol using prostaglandin E 2 (Prepidil) and intravenous oxytocin. Thirty-eight patients requiring induction of labor with an unfavorable cervix (Bishop score Υ
5) were prospectively randomized to receive either 50 mcg misoprostol every 4 hours until delivery, or a single dose of PGE 2 gel (0.5 mg) followed by intravenous oxytocin infusion. Changes in Bishop scores were recorded in a blinded fashion. Clinical outcomes were compared in the two groups, including induction-to-delivery times and cesarean section rates. Seventeen women were treated with misoprostol, 19 patients received PGE 2 /oxytocin, and two patients dropped out of the study. The groups did not differ significantly with respect to age, parity, gestational age, weight, height, reason for induction, or initial Bishop score. There was a significant difference in the median change of the Bishop score among those treated with misoprostol (4) and those of the control group (1) (P Ο½ 0.001). Fifteen (88%) receiving misoprostol delivered within 36 hours compared with 9 (47%) of controls (P Ο 0.01). Significantly more women in the misoprostol arm (8) experienced tachysystole when compared with the control group (0) (P Ο½ 0.01). There were no perinatal morbidities in either group. These data support misoprostol as an effective and economical cervical-ripening and labor-inducing agent.