The risk is thought to be less if you have had a previous vaginal birth or VBAC. From the NHI VBAC statement:
"A prior history of vaginal delivery, either before or after a prior cesarean delivery, is consistently associated with an increased likelihood of VBAC. For example, in one retrospective cohort study, the vaginal birth rate after trial of labor was 63 percent in women with no prior vaginal delivery, 83 percent in women with a prior vaginal delivery before cesarean delivery, and 94 percent in women with a prior VBAC. The rate of VBAC increases with each prior VBAC. Nonrecurring indications for cesarean delivery are also associated with a higher rate of VBAC. For example, compared to arrest of labor, prior cesarean delivery for malpresentation is associated with a higher rate of VBAC. Women who previously delivered babies weighing less than 4,000 grams are more likely to have a VBAC than are those who delivered heavier babies."