C-sections had dropped in the early 1990s after an outcry that American women were getting too many. But in 1997, they started inching back up again. Last year brought the biggest jump yet, a 7 percent increase that "was certainly a surprise," said Joyce Martin, co-author of the Centers for Disease Control and Prevention birth report that was released Thursday.
That made C-sections account for 24.4 percent of U.S. births last year, the CDC found. The nation's high was 25 percent in 1988.
The annual birth report also found:
Teen-age birth rates continued their decade-long drop, hitting a record low of 45.9 births for every 1,000 girls ages 15 to 19. That is 5 percent lower than the rate of 48.5 births per 1,000 girls in 2000.
4.04 million babies were born in the United States last year, a slight drop from the previous year.
The rate of low birth weight babies has remained unchanged since 1998, at 7.6 percent.
Caesareans can be life- or health-saving for many mothers and babies. But a C-section is major abdominal surgery so avoiding unnecessary ones also is important.
Women's risk of death, although small, is three to seven times higher than during vaginal delivery, says the American College of Obstetricians and Gynecologists. They also have longer hospital stays, a higher risk of post-delivery infection and increased pain.
Almost 17 percent of first-time mothers had a Caesarean last year, a 5 percent jump, the CDC reported.
Part of the reason is that more women are opting for a Caesarean even though they are healthy enough to avoid one. There is no data on exactly how often this happens, although "patient-choice Caesareans" are being done around the country.
Some obstetricians say it is wrong to operate without a medical reason while others say it is paternalistic not to let women choose.
But most Caesareans are repeats. Women who had one C-section are very likely to give birth that way again. Last year, the number of prior-Caesarean mothers who succeeded in giving birth vaginally plummeted by 20 percent.
Studies at teaching hospitals sparked the trend of "vaginal birth after Caesarean," or VBAC, in the early 1990s, showing it was safe to try if the previous surgical cut had been made in the lower, not upper, abdomen.
There is a 1 percent risk of a uterine rupture during VBAC, but the few women who do suffer it fare well if they give birth at hospitals prepared to do emergency Caesareans, said Dr. Bruce Flamm of Kaiser Permanente Medical Center in Riverside, Calif., a spokesman for the obstetricians and gynecologists group.
But by the late 1990s, more women who had had Caesareans were having their subsequent deliveries at community hospitals, which are less prepared to offer emergency surgery, he said.
With the growing crisis of affordable malpractice insurance an additional factor, "I don't see any counterbalancing that is going to bring the C-section rate down" any time soon, Flamm said.