Obstetricians perform more cesarean sections when there are financial incentives to do so, according to a new study that explores links between economic incentives and medical decision-making during childbirth.
About 1 in 3 babies born today is delivered via C-section, compared to 1 in 5 babies delivered via the surgical procedure in 1996. During the same time period, the annual medical costs of childbirth in the U.S. have grown by $3 billion annually. There are significant variations in the rate of cesarean deliveries in different parts of the country — in Louisiana, for example, the C-section rate is nearly twice as high as in Alaska.
Obstetricians in many medical settings are paid more for C-sections. In a new working paper published by the National Bureau of Economic Research, health care economists Erin Johnson and M. Marit Rehavi calculated that doctors might make a few hundred dollars more for a C-section compared to a vaginal delivery, and a hospital might make a few thousand dollars more.
Johnson and Rehavi decided to explore the reasons for the increased number of surgical childbirth procedures via an unusual tack: They hypothesized that obstetricians would be less likely to be swayed by financial incentives when patients themselves had significant medical expertise and knowledge. By contrast, the researchers figured, such incentives might play a larger role in medical decision-making when patients knew very little.
In some ways, this is analogous to what happens when people take their cars to mechanics. People who are knowledgeable about cars are likely to push back against unnecessary repairs, whereas those who don't know much about cars are less likely to take issue with the mechanic's advice.
In childbirth, Johnson and Rehavi figured, this meant that obstetricians would perform fewer C-sections when their patients were themselves doctors.
"The idea is that physicians have medical knowledge," Johnson says. "If the obstetrician is deviating from the best treatment because of their own financial incentive, the patient [who is a] doctor would be able to push back against the obstetrician. But that might not be the case for nondoctors because they simply do not have the medical knowledge to know whether or not this C-section is the appropriate [method of delivery] for them."
The researchers tracked large numbers of births in California and Texas via databases that checked to see whether the mothers were themselves doctors.
"We found that doctors are about 10 percent less likely to get C-sections," Johnson says. "So obstetricians appear to be treating their physician patients differently than [they treat] their nonphysician patients."
Johnson says she thinks it unlikely that the doctors are conscious of the role financial incentives seem to be playing in their decisions. Rather, she says, a variety of analyses by economists suggests that incentives affect behavior in many different ways — often subtly.
Indeed, Johnson and Rehavi found that there was no disparity in the C-section rate between physician mothers and nonphysician mothers when the surgical procedures were scheduled in advance. Scheduled C-section decisions tend to be less subjective — a variety of medical conditions, such as a baby being in the breech position, call for a C-section.
Rather, she says, the disparity came about in what are known as unscheduled C-sections, when labor is attempted but does not go well. Patient and obstetrician then find themselves in a gray zone, where a judgment has to be made about whether to terminate labor and deliver the baby surgically.
Johnson and Rehavi also analyzed disparities in medical settings where doctors were paid a flat salary. In these cases, Johnson and Rehavi found there was a disincentive to perform the surgical procedures, which typically involve more time. In these settings, more of the mothers who were physicians received C-sections than mothers who were not physicians. Presumably, Johnson says, this means that some nonphysician mothers who needed C-sections did not get them in these settings.
Johnson suggests that one solution to the disparities lies in better patient knowledge and empowerment.
DAVID GREENE, HOST:
In the last few years we've had a big debate in this country about medical costs. Critics say financial incentives drive up costs and cause doctors and hospitals to deliver unnecessary treatments that are bad for patients. Well, there's new research now that ties incentives like that to the nation's soaring C-section rate. This is, of course, where babies are delivered via surgery.
NPR's social science correspondent Shankar Vedantam joins us often and he's here not to tell us about this. Shankar, welcome back.
SHANKAR VEDANTAM, BYLINE: Happy to be here, David.
GREENE: So money can play a role in the baby business.
VEDANTAM: It seems to, David. You know, look. In 1996, one in five babies in the United States were born via C-section. Today it's one in three. And in that same time period, childbirth costs have grown by as much as $3 billion. Lots of times, C-sections are warranted and necessary. But there is concern that some mothers are getting them when it's not needed.
I spoke with Erin Johnson. She's an economist at MIT. And along with her co-author, Marit Rehavi, they looked at how likely doctors were to get C-sections when they were mothers themselves. So Johnson tracked half a million births in California and a large number in Texas. Here's what she told me.
ERIN JOHNSON: We found that doctors are about 10 percent less likely to get C-sections. So obstetricians appear to be treating their physician patients differently than their non-physician patients.
GREENE: OK. Shankar, why are we comparing the rates of C-sections among moms who are themselves doctors, compared to moms who are not doctors?
VEDANTAM: You know, David, it's what I call the Car Mechanic Rule. Let's say you took your car in and the mechanic told you that you needed a transmission fluid flush. The only way that you can be sure that you're not getting ripped off by your mechanic is if you knew something about your car. You apply the same rule to medicine. Who are the patients who actually know whether a C-section is actually needed? It's other doctors.
GREENE: OK, so the difference we're seeing might be showing us where there are financial incentives at play. And this research is actually saying that doctors might be providing more C-sections when they're paid more.
VEDANTAM: Yes, but a doctor might not be thinking: Here's a chance to make an extra $200, so let me perform a C-section. It's much more subtle than that. It might even be happening at an unconscious level. In fact, Johnson finds that there is no disparity in C-sections when the C-sections are scheduled in advance; these tend to be cut and dried cases, there are clear medical guidelines.
The disparity comes about in unscheduled C-sections. That's where labor is attempted, it isn't going well, and the doctor now has to make a judgment call about whether to stop labor and do a C-section. It's in that kind of ambiguous situation where a judgment call is required that this kind of bias seems to flourish.
GREENE: Is this a pretty clear argument against providing physicians with financial incentives?
VEDANTAM: Not necessarily, David, because Johnson points out financial incentives are not the only incentives out there. In situations where doctors are paid a flat salary and there's no financial incentive, it turns out there are incentives related to time - because C-sections actually take more time for the doctor to do. And in those situations moms who are physicians end up getting more C-sections than mothers who are not physicians.
Presumably the mothers who are physicians are getting the C-sections because they're warranted. And some of the other women, for whom a C-section is warranted, aren't getting them.
GREENE: Shankar, I can imagine people hearing this and being really worried and not wanting money to play a role when they're thinking about procedures like C-sections and other things. What's the take home here? How should people deal with this?
VEDANTAM: Well, Johnson thinks the solution lies in patient knowledge and empowerment, that if you're going to a physician you should actually be asking a lot of questions and try and understand as much as you possibly can about what's going to happen to you when you give birth. In some ways it's the same as the Mechanic Rule, David. You really have to find a doctor whom you can really trust.
GREENE: Shankar, thanks as always.
VEDANTAM: Thanks, David.
GREENE: Shankar Vedantam regularly joins us to talk about social science research. And on Twitter you can follow him @hiddenbrain. You can also find this program @nprgreene and @morningedition. Transcript provided by NPR, Copyright NPR.