Foreword: the tug of war between vaginal and cesarean births.

Cesarean section rates in the United States have now reached their highest levels ever, accounting for one third of all births. This relentless push upward has been driven by a steady increase in primary cesareans and a sharp decrease in vaginal birth after a cesarean. The result? As long as these two trends continue, the total number of cesarean deliveries will continue to increase. Let's examine some of these trends.