Cesarean delivery is the most common surgery performed in the United States, but there is enormous variation in C-section rates across the country, a new study shows; the rates varied from 7.1 percent in some hospitals to 69.9 percent in others, driven largely by differences in practices at individual institutions.
The overall C-section rate in the U.S. has increased from just under 21 percent of all deliveries in 1996 to nearly 33 percent in 2011, according to the Centers for Disease Control and Prevention. Health policy experts typically ascribe that leap to increased rates of maternal obesity, gestational diabetes and multiple births in the U.S., as well as doctors' concerns over malpractice.
But the new study, published in the journal Health Affairs this week, showed a much bigger increase among women who were low-risk patients. Because they did not have the factors that might increase their odds of having a C-section -- preterm birth, a breech baby, multiples or a history of C-section -- the investigators expected to see less variation from hospital to hospital in their Cesarean rates. Instead, hospital C-section rates in that group varied from 2.4 to 36.5 percent.
"The variations we uncovered were striking in their magnitude, and were not explained by hospital size, geographic location or teaching status,” said lead author Katy Kozhimannil, an assistant professor in the University of Minnesota School of Public Health in a statement. “The scale of this variation signals potential quality issues that should be quite alarming to women, clinicians, hospitals and policymakers.”
Kozhimannil and her colleagues relied on federally collected hospital discharge data from 593 hospitals across the country and more than 817,000 babies born in 2009. Previous studies have analyzed geographic differences in C-section rates, focusing on state and country-level data. But the new paper is among the first national studies to look at variations from hospital to hospital, the authors write.
What is not clear from the hospital discharge forms is why the C-sections were performed, nor do the forms provide information on individual hospitals' care guidelines. But findings suggest the rate variation largely stems from care patterns at different institutions.
"There's a wide variation and you can't really say it's due to the type of patients that go [to a hospital], or the type of hospital it is -- whether it's big or small, teaching or non-teaching ..." said Dr. Christopher Glantz, a professor in the Department of Obstetrics and Gynecology at the University of Rochester who has done research on elective induction and Cesarean deliveries, but did not work on the new study.
"You're left saying, 'It must just be the styles of practice of individual doctors,'" he said, adding that there has been a shift in recent years toward women and their partners expecting and even asking for more interventions.
Women who are concerned about C-section rates should ask for data from their hospital, which is generally available online, Glantz added. What can be more difficult, if not impossible to find, are individual providers' rates. The Department of Health and Human Services has developed public health strategies to decrease the number of C-sections in the U.S., setting a goal of lowering the rate by 10 percent by 2020.
But Glantz said it often comes down to, 'If your doctor says you need to have a cesarean, the patient tends to have a cesarean."