If you’re a first-time mom, your chances of having a Caesarean section could vary dramatically depending on which medical clinic you choose.

A survey of Minnesota clinics found that C-section rates varied from as little as 3 percent of births to more than 50 percent across the state last year. The state average was 26 percent for first-time mothers, according to the report by MN Community Measurement.

“We can’t explain all of the differences,” said Jim Chase, president of the organization, which compiles an annual report comparing Minnesota medical clinics on various health measures. “What’s important is to see that there is quite a variation.”

The 2012 report, released Tuesday, spotlights a growing concern in the medical field: why C-section rates have climbed to a third of all births nationwide. In Minnesota, the number jumped from 17 percent of births in 1996 to 26 percent in 2007, the last year data were reported.

The report did not track whether the C-sections were medically necessary. But Chase said the wide variation should prompt discussion among doctors and patients. “It doesn’t appear to be solely driven by medical necessity,” he said.

This year, for the first time, hundreds of clinics reported their C-section rates, along with data on more than a dozen other medical conditions, for Minnesota’s annual Health Care Quality Report.

It found that Hennepin County Medical Center’s Brooklyn Park clinic had the lowest C-section rate in the state, at 3 percent. Two other clinics had C-section rates under 10 percent: Fairview Andover and Oakdale Ob/Gyn.

At the other end of the spectrum, two clinics reported rates of more than 50 percent: Chippewa County Montevideo Hospital and Fairview Princeton Clinic.

The report sent some clinic officials scrambling to explain the numbers.

Data viewed with caution

Mark Paulson, the administrator at Chippewa County, said he believed a reporting error exaggerated his clinic’s C-section rate. “We know that that number is out of the ordinary,” he said, adding that an internal review found a 12 percent C-section rate for first-time mothers last year. “We are trying to verify the numbers,” he said.

The report’s authors caution that small numbers of patients can skew the results at sites like Chippewa County and the Princeton clinic, which reported fewer than 75 deliveries last year.

But they also found that C-section rates varied dramatically among medical groups with multiple clinics. The best group, it found, was Winona Health, with a 14 percent C-section rate.

Dr. Scott Birdsall, an obstetrician at Winona Health, said the low numbers reflected the staff’s restrained approach. “We’re not necessarily slow to go to C-section, but we try to avoid that if at all possible,” he said. “I think we’ve been very successful.”

‘Starts the discussion’

The report also cited Olmsted Medical Center, North Clinic and Hennepin County Medical Center as among the state’s top performers, with C-section rates of 20 percent or less.

By comparison, the Mayo Clinic Health System, Southdale Ob/Gyn and Stillwater Medical Groups had rates over 30 percent, while a few others approached 40 percent.

Dr. Ola Famuyide, chair of obstetrics at the Mayo Clinic, praised MN Community Measurement for shining a light on the variations.

“That starts the discussion,” he said, but he cautioned against “reading too much into this information right now.” He said they need to understand why the variations occur, and whether the rates are driven by medical necessity or other factors.

Dr. Annelise Swigert, an obstetrician at Southdale, agreed. “As obstetricians, we feel this is an important issue to look into,” she said. She noted that her practice, like many big-city clinics, tends to see more high-risk patients than small-town clinics. At the same time, she said there’s a growing recognition in the field of the need to find ways to lower the rate, especially for uncomplicated pregnancies. “That’s where we can make a difference,” she said.

Chase noted that some small clinics routinely refer high-risk patients to larger centers, making their own C-section rates artificially low.

In addition to C-section rates, the new report tracks clinic performance on 18 other medical conditions, including diabetes care, depression care, colon cancer screening and vaccination rates. It can be found at www.mncm.org.