What Explains Variation in Cesarean Rates Between Hospitals?
By Rachel Walden — March 27, 2013
While cesarean rates (which reached an all-time high in 2007) are known to vary widely by state, they also vary quite a bit by hospital. One common explanation for this has been that different hospitals have different c-section rates because they see different types of patients – patients who are sicker or healthier, or more likely to have complications requiring cesarean.
In an article published in PLOS ONE, researchers report findings from a study designed to look at other factors that influence cesarean rates. The authors looked at birth certificate and hospital discharge data in Massachusetts to determine which factors were linked to cesarean rates at each hospital.
The researchers focused on first births of single, non-breech births in Massachusetts hospitals from the beginning of 2004 through the end of 2006. They report that at the hospital level, the percent of cesarean deliveries varied between 14.0 percent and 38.3 percent (average of 26.4 percent). Then they adjusted for health and sociodemographic factors, like labor induction and maternal age, that are linked to higher rates of cesarean.
They found, predictably, that individual risk for cesarean varied by demographic, socioeconomic, pregnancy, and preexisting medical conditions. After they adjusted for these factors, though, there was still significant variation in rates between hospitals that could not be explained by those medical and personal risk factors.
While the authors did not set out to explain why this variation occurred, they note that it has been observed in other studies (such as in Arizona, and in military hospitals), and that contributing factors may include liability- and insurance-related factors, whether a woman delivers at a teaching hospital, the provider’s approach to delivery, hospital practices related to labor induction and augmentation, and others. They conclude that additional research is needed on hospital characteristics to figure out what is driving variability between hospitals and reduce the influence of non-clinical factors on women’s risk of cesarean delivery.
Finding out the rate of cesarean sections at any given hospital can be difficult, as is understanding why the rates are high in any given situation. At her website, CesareanRates.com, consumer advocate Jill Arnolds attempts to bring together the available statistics, allowing users to compare cesarean rates by state and by individual hospital.
If you’re interested in finding out more about what you can do increase your chances of having a vaginal birth, see this tip sheet from Childbirth Connection.
Curiously, the authors make no effort to determine if different rates produce different outcomes. A lower C-section rate is not necessarily better and may lead to poorer outcomes. A survey of C-section rates without reference to outcomes has very little value.
Thanks for commenting – I would definitely be interested in how rates are or are not associated with outcomes, although that was not the intent of this study to address. Instead, they seem to have intended specifically to explore the notion that case mix itself is able to explain the variation in rates between hospitals, given that case mix not uncommon guess as to why some hospitals have much higher or lower rates. A nice next step would be to figure out what difference it makes for women and babies, how outcomes vary across hospitals, and if there is any association between the two. It’s fair to say that not doing cesareans when needed could have poor outcomes, and on the other end there are the potential risks from cesareans as well (such as those listed in http://transform.childbirthconnection.org/wp-content/uploads/2013/02/Cesarean-Report.pdf – which vary in how common and severe they are, but I think are worth thinking about). It seems an interesting question of what does influence those rates outside of medical indications, and of course how those influences and varying rates affect outcomes for both babies and women. So I don’t think we disagree that we’d like to know more about those outcomes, just that I don’t think these authors intended to answer that particular question with this study.
The researchers didn’t look at the factor that is probably most important for reducing cesarean rates—the extent to which CNMs manage and attend the births of normal-risk women at particular hospitals. It is clearly not just the patient mix, as in the past, cesarean rates were higher for the lowest-risk women, although I haven’t looked at that relationship for a long time. But if researchers really want to know what drives the cesarean rate down while maintaining excellent outcomes (I agree with Dr. Tutuer), look at the role of midwives in the care of normal-risk women during labor. I would also look at whether all incentives to deliver a woman within a certain period of time — e.g.,, hospitalist care vs. physicians who may have surgery scheduled for the next morning or a waiting room of patients to attend to and are at the hospital waiting for labor to take its course—whether that kind of time pressure exists or not.
Thanks for your comment as well, Judith.