Depends what country you’re in maybe, but if a mother has had a previous classical, so cesarean birth, which is usually a vertical incision on the uterus, then those moms are advised not to have a trial of labor mainly because when the uterus contracts it starts from the top and if there is a scar at the top that has played into for the course of the labor and there can be some weakness in that such that in mothers with the previous classical incision, there’s about a one in 20 risk of it’s separating. There’s about a five percent risk of a uterine rupture. Whereas if she’s had a low transverse lower part of the uterus, a previous surgical birth with the constant contractions at the top doesn’t bother the low part too much. Such that the risk of a complication is about one and 200, zero point five percent. So in the scenario in which there is a vertical incision on the uterus is a higher risk of there being a uterine separation or also known as uterine rupture. For those moms are advised not to have a trial of labor.