INDUCED MULTIPAROUS WOMEN MATTHEW HOFFMAN, ANTHONY SCISCIONE, ANJEL VAHRATIAN, JAMES TROENDLE, JUN ZHANG, Christiana Hospital, Newark, DE None Given, Newark, DE University of North Carolina at Chapel Hill, Maternal and Child Health, Bethesda, MD National Institutes of Health, Epidemiology Branch, Bethesda, MD OBJECTIVE: The incidence of labor induction is rising rapidly in the United states. The labor in these women is often followed with traditional labor curves derived from uninduced pregnancies. We sought to determine how the labor curves of women who presented in spontaneous labor differed from those who were electively induced with and without pre-induction cervical ripening. STUDY DESIGN: We studied the labor curves of all multiparous women with a singleton vertex fetus between January 2002 and June 2003 at a single institution. We excluded women who had diabetes, contraindications to vaginal delivery or othermaternal/fetal indications for delivery. For the analysis, women were categorized as spontaneous labor(LABOR), electively induced(INDUCED) or induced with pre-induction cervical ripening(RIPENING). Labor curves were generated using interval censored regression after adjusting for confounders. RESULTS: Two thousand and seventy women were included in the study(66% LABOR, 30% INDUCED, and 4% RIPENING). Patient characteristics are presented in Table 1 and labor progression in Table 2. CONCLUSION: Compared to women in spontaneous labor, women who were induced without pre-induction cervical ripening had a shorter active phase. In contrast, women who underwent pre-induction cervical ripening had a slower latent phase and similar active phase when compared to those in spontaneous labor.