Over the past few years, it seems the eligibility requirements for Cesarean sections have become muddled. They’re supposed to be reserved for mothers who aren’t able to have a safe vaginal delivery, or who have certain medical problems. However, an increase in medically unnecessary C-sections, at least partially, contributed to 12 years of increasing rates, topping out at 32.9 percent of all births in 2009. Just last year, the American College of Obstetricians and Gynecologists (ACOG) had to revise guidelines to discourage doctors from performing them before 39 weeks. But even with a plateau in rates and the new guidelines, hospitals are still performing them, according to a new study, and the variability with which they’re doing so calls into question: why?

The study, conducted by researchers at the University of Minnesota, Minneapolis, and involving over 1.4 million births in 1,373 hospitals, found that there was a high variability between the chances a woman would get a C-section at hospitals. Overall, all women faced a 19 to 48 percent chance of having a C-section, while women who had never had one before had an 11 to 36 percent chance. Even when women were at a lower risk for having one, they faced an eight to 32 percent chance of still undergoing the procedure. Higher risk women, meanwhile, faced a 56 to 92 percent chance. Even after adjusting for maternal diseases like diabetes, hypertension, hemorrhages, fetal distress, and obstructed labor, the variability didn’t change.

Such variability puts women’s health at risk, since care should be consistent between every hospital and C-sections pose their own risks in and of themselves. But if women aren’t getting C-sections because of a medical condition, then what’s motivating these hospitals to perform the procedures?

Professor Katy Kozhimannil, lead researcher of the study, said that C-sections pay about 50 percent more than vaginal births, but although that probably doesn’t play a role in doctors’ decisions, it could influence policies at a higher level. “There needs to be clear, evidence-based protocols … so that providers and clinicians have good guidance about how to treat people with particular … conditions,” Kozhimannil told the StarTribune. “Women who are clinically the same should have similar clinical care.”

Over and above that, medically unnecessary C-sections that occur before the recommended 39 weeks could have health implications for the baby. A study published earlier this month found that babies born with a low birth weight were less likely to perform well in school when compared to those that were a little heavier. With C-sections believed to be associated with lower weight births, it’s really up to moms to try to avoid medically unnecessary procedures.

Source: Kozhimannil K, Arcaya M, Subramanian SV. Maternal Clinical Diagnoses and Hospital Variation in the Risk of Cesarean Delivery: Analyses of a National US Hospital Discharge Database. PLOS Medicine. 2014.