While a trial of labor after a previous cesarean section is associated with a slightly higher risk of uterine rupture than a repeat surgical delivery, the additional risk is less than previously thought.  

A systematic review of  the research literature determined that women who have had a previous C/S and who elect a trial of labor have an increased risk of uterine rupture of 2.7 per 1,000 cases, compared with women who elect a repeat cesarean delivery. Put another way: 370 elective cesarean deliveries need to be performed to prevent one symptomatic uterine rupture.  

In addition, most uterine ruptures do not have serious consequences. In the studies reviewed, no maternal deaths were related to rupture, the additional risk of perinatal death from rupture of a uterine scar was 1.4 per 10,000, and the additional risk of hysterectomy was 3.4 per 10,000.

While a trial of labor after a previous cesarean section is associated with a slightly higher risk of uterine rupture than a repeat surgical delivery, the additional risk is less than previously thought.