Aug. 30, 2010 -- Cesarean section deliveries are at an all-time high in the U.S. and are expected to keep rising, and new government-funded research may help explain the trend.

Nearly one in three babies are now delivered surgically -- up from one in five just over a decade ago.

Previously recognized contributors to the rise include delayed childbearing, the rising obesity rate among moms-to-be, and an increase in multiple birth deliveries.