PROJECT ABSTRACT Most pregnant women with one prior cesarean birth are appropriate candidates for trial of labor after cesarean (TOLAC), yet only about 20% of U.S. women with a prior cesarean have a TOLAC. Repeat cesarean is by far the most common indication for cesarean delivery; therefore, increasing access to TOLAC is an important mechanism for reducing the rate of cesarean delivery. However, little is known about how specific experiences in the first pregnancy, birth, and postpartum period – particularly those measured prospectively – impact the development of delivery mode preferences for a subsequent birth, and how these preferences translate into delivery mode decisions. There is a critical need to better understand the experiences shaping women's delivery mode preferences in order to guide future research testing approaches to support shared decision making in this population. This study will use data from a large-scale, prospective cohort to address the following specific aims: 1) To determine how experiences in the first pregnancy, birth and postpartum period shape women's preferences for delivery mode after a first birth by cesarean, reported during the next pregnancy; and 2) To examine the relationship between delivery mode preferences and subsequent trial of labor and VBAC among women who had a second birth during the study follow-up period. The results of this study will provide information directly relevant to clinicians who are seeking to understand women's mode of delivery preference after first delivery by cesarean (VBAC or repeat cesarean) and to work toward decisions with their patients about whether or not to have a trial of labor, taking into account both preference and risks. This research will add to the evidence base for future studies developing interventions to support shared decision making regarding trial of labor after cesarean.