A California study found that the percentage of mothers who had had a child by Caesarean section and opted to repeat the procedure for subsequent children increased during the second half of the 1990s, the Centers for Disease Control and Prevention said Thursday.
That is a reversal of the trend from the 1980s and early '90s.
Nearly a quarter of all deliveries in the country are by C-section. The United States is trying to reduce that to about 15 percent. Since 2000, the government has been promoting vaginal births, contending they carry a lower risk of medical complications for mothers.
But the California study casts doubt on whether the government can reach its goal. The CDC found that the percentage of women who chose a vaginal birth after having their previous child by C-section dropped from 23 percent to 15 percent between 1996 and 2000.
The CDC said the study supports other research indicating the same thing is happening nationwide.
California, which accounts for one-eighth of all births in the United States, will probably not meet the government health goals on Caesarean sections, the CDC said.
"California has the largest population of births in the country, so whatever happens here will be seen nationally," said the CDC's Dr. Sharon Durousseau.
The government has set a goal for 2010 of 37 percent of women having vaginal births after having Caesareans. The U.S. rate now is 22 percent.
The government cited medical and legal pressures for the increase in C-sections among these women.
Similarly, doctors said Caesarean sections are on the rise because it is convenient for health providers and patients to schedule births; because of the risk of lawsuits if something goes wrong with the baby; and because the stresses of labor can cause bladder problems in the mother.
Many obstetricians have long believed that once a woman gave birth by C-section, all subsequent deliveries would have to be done that way, too, because of the risk that the scarred uterus could rupture during labor if the mother attempted a vaginal birth. But in the 1990s, government experts concluded that many of these women could safely deliver vaginally.
Dr. Curtis Lowery, director of the maternal-fetal medicine division of the obstetrics and gynecology department of the University of Arkansas for Medical Sciences, said almost none of hospitals in Arkansas are performing vaginal births after Caesareans.
C-sections are "not an effective spending of health care resources," Lowery said. "What will happen as the result of multiple abdominal surgeries on patients?"
Federal officials said better education campaigns for women and health-care providers on the risks and benefits of vaginal births are needed.