The most serious risk of a trial of labor is that a C-section scar could come open during labor. This is very rare. But when it does happen, it can be very serious for both the mother and the baby. The risk that a scar will tear open is very low during VBAC when you have just one low cesarean scar and your labor is not started with medicine. This risk is why VBAC is often only offered by hospitals that can do a rapid emergency C-section. If you have a trial of labor and need to have a C-section, your risk of infection is slightly higher than if you just had a C-section.