Why wildly varying C-section rates persist

For a baby born in the U.S., the likelihood of entering the world through the birth canal or by cesarean section is not based strictly on clinical factors. Insurance coverage and the hospital where that baby is delivered also play a role.

Last year, about a fifth of all babies born at DMC Harper-Hutzel hospitals in Detroit were delivered by C-section. At two nearby hospitals, Henry Ford West Bloomfield Hospital and McLaren Macomb in Mount Clemens, Mich., a quarter and well over one-third of the babies were, respectively.

The rate of babies born by C-section varied by 15.3 percentage points across the three hospitals, according to data they submitted to the Leapfrog Group, an employer-backed quality and patient-safety group in Washington, D.C.

But the numbers don't explain why a higher proportion of babies were born by C-section at McLaren Macomb than at Harper-Hutzel.

Figuring out those drivers can lower the nation's high C-section rate and related healthcare spending. But there's a dearth of information about how delivery decisions are made at each hospital.

“One of the things we don't know a lot about in maternity care is hospital management practices,” said Katy Kozhimannil, an associate professor at the University of Minnesota School of Public Health. “Obstetrics is not the most lucrative service line for healthcare delivery systems, so it's not the place where most attention goes.”

High and wildly varying rates of C-sections across the U.S.—and the reasons for both—are well-established. Insurers pay more for C-sections than vaginal births, which take more time in hospitals that are often pressed for space.

Doctors also fear malpractice suits stemming from natural births, even though C-sections are considered riskier than vaginal births unless medically necessary. Accounting for nearly one-third of births in 2014, C-sections in the U.S. are performed at double the rate the World Health Organization considers medically necessary.

The average rate of C-sections among women considered less likely to need the procedure—first-time mothers with a single baby at term and positioned head-down—was 25.8% among hospitals that reported to Leapfrog in 2016. That C-section rate fell less than 1 percentage point from the year before, when the average rate was 26.4%. Meanwhile, rates varied wildly by state, from 17.1% in New Mexico to 32.1% in Louisiana.

Kozhimannil, who reviewed the report, said the variability was striking. Her own research corroborates Leapfrog's findings. C-section rates varied at least tenfold across 593 U.S. hospitals, from 7.1% to 69.9%, according to a Health Affairs study she co-authored in 2013.

The state of California, which has been working on lowering its C-section rate, has what experts call unusually good data on C-sections thanks to an online database that gathers hospital discharge records with birth certificate data. The data shed light on individual doctors and track procedures and flag problems that lead to more C-sections.

Sometimes, C-sections are medically necessary, depending on the mother's risk factors—obesity, drug addiction or lack of prenatal care, to name a few examples—and so the data need to go deeper, to allow for risk adjustment and to reveal the deciding factors that led to a C-section.

“The system nudges hospitals and clinicians toward greater use of cesarean sections,” Kozhimannil said. A C-section can take 30 minutes, making them much more appealing to doctors, hospitals and patients. Plus, Medicaid and private insurers typically pay twice as much for a C-section. The Center for Healthcare Quality and Payment Reform has estimated the average commercial payment for vaginal births to be $5,809, compared with $11,193 for cesarean births.

Some areas of maternity care are straightforward to improve. To stop early elective deliveries, for instance, hospitals or payers can put a hard stop to them. They can refuse to schedule C-sections or to pay for deliveries when labor is induced without medical necessity. Some states have done this with their Medicaid programs.

With C-sections, it's more challenging. Payment reform to reduce financial incentives for C-sections has been limited to a handful of pilot projects, including bundled payments that pay the same amount for a delivery, be it vaginal or cesarean section.

Hospitals should recognize that patients and insurers are paying attention to C-section rates and other maternity care metrics, Leapfrog spokeswoman Erica Mobley said. “Some hospitals are performing much better than others. There are lessons to be learned.”