Figures released Thursday show what appears to be a significant shift in when pregnant women have cesarean sections. Experts called the change great news — apparent evidence that doctors and women have absorbed warnings about the risks of C-sections and the importance of waiting to deliver until the baby is full-term.
"People are getting the message," said Dr. Barbara Stoll, an Emory University specialist in the care of newborns.
A C-section is major surgery with risks of infection and, in very rare cases, death. Recovery time is longer than with a vaginal delivery. And the babies can be more likely to have breathing difficulties and other medical problems.
For decades, the operations were done in only a small fraction of births, usually only when a fetus was in danger. In 1970, the U.S. rate was 5 per cent of all births.
By 2009, about a third of births were C-sections. Experts say many factors drove the rate up, including the convenience of scheduling deliveries.
But that rate has at least stopped rising for two years. The overall rate was again about 33 per cent in 2011, the latest year available from the Centers for Disease Control and Prevention.
Thursday's report focused on preliminary data for that year's single-child deliveries, which are about 96 per cent of all births. The trend there was similar to the overall numbers: The C-section rate has held steady at 31 per cent since 2009, after rising for a dozen straight years.
The report found very little change in C-sections through 37 weeks of gestation between 2009 and 2011. But at 38 weeks there were fewer: the rate fell 5 per cent, to 32 per cent.
And at 39 weeks, it rose 4 per cent, to 34 per cent of births. The rate at 40 weeks held steady at 25 per cent.
A full-term pregnancy is 39 to 40 weeks. The changes occurred across the board, for all major racial and ethnic groups and for all ages of mothers.
CDC health statistician Michelle Osterman said they had hoped to figure out from the report why the overall rates had levelled off, but it didn't provide any answers. Health officials want to push the rate down to a goal of 15 per cent.
Still, the shift to later C-sections is great news, said Dr. George Macones, head of obstetrics and gynecology at Washington University in St. Louis.
"The important thing is babies born before 39 weeks have more complications than babies born at 39 weeks and beyond," Macones said.