JOHN YANG: Cesarean section surgeries or C-sections to deliver babies are the most common surgical procedures in U.S. hospitals.

Now, a new study of nearly 1 million births from 2008 to 2017 finds that black women are almost 25 percent more likely than white women to have unnecessary C-sections, needlessly putting them at risk of surgical complications.

The study is from the National Bureau of Economic Research and was done by three economists.

Sarah Kliff is an investigative healthcare reporter for the New York Times.

Sarah, your story, writing about this, you had a wonderful way of describing it.

You had an example of, or a hypothetical, a black Mother and a white mother.

Same medical history, same doctor, same hospital.

SARAH KLIFF, Investigative Healthcare Reporter, The New York Times: Yeah.

So they walk into the same hospital, they have the same doctor.

On paper, their medical records look basically identical.

But the black woman has a 20 percent higher chance of delivering by C-section, which really begs the question, you know, why is this happening?

JOHN YANG: Was there answer to that in this study?

SARAH KLIFF: Thereús not one answer.

There are some theories, and we canút exactly get inside the doctorús heads.

It could be that they are aware that black women have higher rates of maternal mortality.

So theyúre thinking, Iúm going to get this person into surgery faster.

I donút want to risk complications.

It could be that they arenút listening to black mothers as much.

If theyúre pushing back against the idea of a C-section, itús difficult to tell.

But we definitely know that something different is happening for these black women.

JOHN YANG: And we should say that there are reasons why, medical reasons, why a doctor would schedule a C section, that the benefits outweigh the risks.

But what are the risks of an unscheduled, an emergency C-section on a woman who has no complications?

SARAH KLIFF: Yeah, I mean, itús pretty much the risk of adding a major surgery onto the delivery.

C-section is a major abdominal surgery.

Thereús the risk of an infection, of a hemorrhage.

These are rare risks, but they are added on.

When you do a C-section.

There is the increased recovery, which is happening when you have a newborn, which, as any parent knows, is a really challenging time already to have a major surgery youúre recovering from.

Thereús also financial risks.

C-sections are more expensive, so the patient could end up with higher bills from their delivery if that is how they end up delivering.

JOHN YANG: Now, the researchers looked for correlations.

They couldnút find any correlations with medical risk factors with the gender of the doctors or the economic status of the mothers.

But they did find one interesting correlation.

SARAH KLIFF: Yeah, the fascinating thing they were able to look at is what was going on in the rest of the hospital and if the operating room was empty.

And I think this was probably the most interesting finding to me was that when the operating room was empty, thatús when black women were significantly more likely to have C-sections than white women.

When the hospital was busy, people are rushing around, but if someone really needs that C-section, black and white women end up getting C-sections at near identical rates.

Itús when the hospital is less busy, when the OR is sitting there empty.

Thatús really when you see these unnecessary C-sections happening on these black mothers.

JOHN YANG: Knowing what you know about from reporting, covering this, how the hospitals work, the implication is they want to keep that operating room busy.

SARAH KLIFF: Look, most of the American healthcare system, itús paid on what we call a fee for service system.

Every time you do an MRI, every time you do an operation, you are getting paid for that service.

You know, werenút able to talk to the doctors or hospitals.

This is an academic study, and I will say the rates of C-section are higher for both black moms and white moms when the OR is empty, which suggests maybe conscious, maybe unconscious.

But there is more of a propensity to send women to C-section when the capacity is there for them.

JOHN YANG: And black women have long talked about different treatment in their pregnancies.

A feeling like their doctors arenút listening to them, not taking their pain into consideration.

Is this part of that?

SARAH KLIFF: Yeah, certainly.

You know, Iúve written some stories about patients who just feel like they werenút listened to, that they asked for an epidural and it took a long time to get it, that they said, I want to try natural labor longer.

And they were really told, no, you need to go to a C-section.

And I think itús, again, difficult to untangle the role of race in all of this, but it certainly is an experience of a lot of black women that they feel like their providers arenút necessarily listening to what they want.

And they might be listening better if their skin was another color.

JOHN YANG: Is there some thought or an indication that this could be a contributor to the fact that black women have higher rates of maternal mortality and childhood infant mortality?

SARAH KLIFF: Certainly.

I mean, C-section, again, is a procedure thatús generally safe, but it comes with its risks.

So if youúre going to add on a major abdominal surgery, thatús essentially increasing your risk for something to go wrong during childbirth.

And, you know, there are many stories out there you can hear of, you know, black women who tried to raise concerns during their delivery.

They werenút listened to and ended up having a bad outcome.

So that certainly could be a part of this story.

JOHN YANG: All these factors put together, the hospitals wanting to keep the ORs busy, black women disproportionately being sent there.

What does this say or suggest about the state of health care in America right now?

SARAH KLIFF: It suggests that a lot of the things that determine the health care you get, they arenút about your medical records.

They arenút about what you actually need.

Theyúre about all these other factors, the color of your skin, whether the operating room is available, itús sitting empty, that the health care that weúre all receiving, itús not just about what we need, but all these other factors that are completely out of our control are contributing to the care that we get.

JOHN YANG: Sarah Kliff of the New York Times, thank you very much.

SARAH KLIFF: Thank you.