Los Angeles ? Cesarean deliveries have doubled since 1996 and now account for one-third of all births in the United States. A new study suggests that a big dose of patience on the part of women and their health care providers during delivery might help to lower the rate substantially.

The study, released Monday by the Eunice Kennedy Shriver National Institute of Child Health & Human Development, found C-section rates were twice as high after induction of labor compared with women undergoing spontaneous labor. Labor is often induced to speed up labor and delivery.

“Our study cannot directly say induction causes C-section, but it does provide some clue that either people may not be patient enough or something is going on that we’re not really sure about,” said the lead author, Dr. Jun Zhang.

The study showed, not surprisingly, that the major reason for undergoing a cesarean was due to the woman having a prior C-section. Still, almost half of the cesareans that took place after labor had started were due to “failure to progress,” and the study suggests that doctors aren’t acknowledging that labor takes time and doesn’t follow a predictable pattern in women, especially first-time mothers. A high proportion of these C-sections were performed before the women’s cervix had dilated to 6 centimeters, which is still considered an early stage of labor, and among women who had been in active labor for only two or three hours.

The study, on 230,000 deliveries at 19 hospitals across the U.S., also found that women who tried to have a vaginal birth after cesarean — or VBAC — succeeded only 57 percent of the time. That number is lower than the estimated success rate of 60 percent to 80 percent found in other studies.

The study implies the high C-section rate is not being driven by women who are “too posh to push.” Researchers found “truly elective” cesarean delivery accounted for 9.6 percent of all scheduled C-section and 2.1 percent of cesareans that occurred after labor had begun.