A cesarean section, also called a C-section, is surgery to deliver a baby through the abdomen. It's used when:

• it's impossible or not advised to deliver the baby through the vagina
• continuing in labor seems to present a greater risk to the health of the baby or mother, even if the plan was a vaginal delivery.

A C-section sometimes is scheduled in advance. But it may also be unscheduled as circumstances change in the course of labor and delivery. An unscheduled cesarean is not the same as an emergency cesarean, which is done when there is immediate risk to a mother or baby that cannot be resolved without immediate delivery.