But change is underway. The Institute for Healthcare Improvement's Strategic Partners program trains hospitals to implement a set of guidelines, such as the careful use of oxytocin, and a ban on elective deliveries before 39 weeks. In four years, 60 hospitals have signed on.
"It's a culture change," program director Frank Federico said. "We're at a tipping point. . . . It used to be that we spent more time defending the 39-week rule. Lately, there's no question about that. It's, 'How can we improve the process to support that?' "
WellPoint Inc. and UnitedHealthcare Services Inc., the nation's largest health insurers, also are trying to curb cesareans.
In an analysis of its claims, United found that 48% of newborns admitted to neonatal intensive care units were from scheduled deliveries, many of them before 39 weeks.
United targeted a group of Texas obstetricians with particularly high rates of deliveries before 39 weeks.
An analysis showed that the babies these doctors delivered were admitted to neonatal ICUs twice as often as the national average.
After being notified of the correlation, the physicians changed their practices and reduced neonatal ICU admissions by 46% in three months.
The rise in avoidable first-birth cesareans has had a multiplier effect. Most U.S. physicians discourage vaginal deliveries after a cesarean because of some widely publicized cases several years ago in which the uterus split disastrously along the prior incision.
That's why Ruby Wales' first obstetrician refused.
"She said it was because there is a 1% chance of a uterine rupture," Wales said. "And I thought that was weird because there's more chance of things going wrong with a cesarean section."
But some obstetricians believe that new evidence supports allowing some women the option of trying for a vaginal birth.
"If the old incision was a vertical, then a trial of labor is not a good idea," said Dr. David Lagrew, medical director for the Women's Hospital at Saddleback Memorial Medical Center in Laguna Hills. "But what happens now in the United States is the low transverse, an incision in the bottom part of the uterus, from side to side. Those heal better. All the studies say, in those types of incisions, the risk is less than 1%, probably a half percent, that it will open during labor."
Saddleback delivers about 3,000 babies a year. In March, it joined a few hospitals nationwide that are pioneering the "hospitalist" approach to maternity care, which adds a measure of safety to attempted vaginal births after cesareans. A hospitalist is a doctor who cares only for hospitalized patients.
Hospitalist obstetricians staff the maternity ward 24 hours a day, seven days a week. They are there to deliver babies when an attending obstetrician gets stuck in traffic, to monitor lengthy labors and to assist in emergencies.
Saddleback supported Wales' desire for a vaginal birth. Nine days after her due date and after 30 hours of labor, she gave birth -- the way she wanted -- to an 8-pound, 11-ounce boy.
"I was so glad nothing happened at the last minute to have an emergency C-section because I'd gone through all this work," said Wales, resting in her hospital bed with baby Carson in her arms. "I'm so relieved that I don't have to deal with a [cesarean] recovery because I have a 2 1/2-year-old at home who is very active."