Taking Race Out of an Equation for Childbirth

Until last week, a calculator widely used by OB-GYNs pushed more Black and Hispanic women toward second C-sections

A pregnant person of color sitting on a bed holding their pregnant stomach. Photo: Getty Images

Torri Mockler didn’t want another cesarean section. She felt bullied into one when she delivered her first child at 23-years-old, and didn’t want to go through the experience a second time.

That’s one reason Mockler, a former gymnastics teacher and current stay-at-home mom in Strafford, N.H., chose to have her second child at a birthing center highly supportive of vaginal deliveries. But a few factors were working against her.

First, vaginal childbirth is considered somewhat risky for people who have had C-sections because the scar that the procedure leaves can sometimes reopen. But research has found that the risks of a vaginal birth after a C-section (VBAC) are often offset by important health benefits, such as lower infection rates and lower odds of problems with future pregnancies.

More on Health and Race

The second factor: Mockler identifies as Black, and Black and Hispanic women are more likely than white women to be nudged toward C-sections if they’ve already had one, according to researchers who study health disparities.

Over the past 10 years, one reason for this has been a simple calculator that helps patients and doctors decide when it’s safe to try for a VBAC. The tool, which often looks like an online questionnaire, takes into account factors that include the mother’s age and body mass index, and whether she’s had a vaginal delivery in the past. Then it offers a predicted chance of a successful VBAC, one that doesn’t end in an unscheduled C-section. There’s no strict cutoff, but anything below 60 percent is often considered too risky.

In 2018, when Mockler sat down with an obstetrician to discuss her delivery, the doctor started entering data into the calculator. After recording her age, height, and weight, he asked, “What’s your race?” 

Mockler didn’t have a simple answer: Her mother is Black and Native American, and her father is white.

“So, Black,” Mockler remembers the doctor saying before he chose “African American.” 

Mockler didn’t know it at the time, but that decision lowered the number that the calculator spit out. She doesn’t remember the figure, just that the doctor said it was “lower than he would’ve liked.” He pushed for Mockler to schedule a C-section, but she refused.

A few weeks ago, Mockler and I roughly reconstructed the consultation by using her age in 2018, along with her height and weight. When we marked her as African American, the calculator estimated a 49.5 percent chance of a successful VBAC, putting her under the rough 60 percent threshold.

But when we didn’t label her as African American, the number went up to 65.7 percent.

Mockler was astonished by that gap. “I don’t think it’s fair,” she said. “It’s racist; I don’t know what else to say.”

A growing number of doctors and researchers say the race adjustment is inappropriate and misleading. Just last week the celebrated obstetrician who created the calculator in 2007 revised the tool to remove race and ethnicity from the equation, a shift that’s part of a movement across medical specialties to rethink the role of race in clinical algorithms.

Race Is Not a Biological Factor

The calculator is based on an earlier study that found that VBACs are on the whole more successful when women have lower BMIs, are white, have private health insurance, and are married, among other factors. When researchers used that data to create the calculator, they tossed out most of the social factors, including insurance and marital status—but they included race and ethnicity.

That was a mistake, medical researchers and practicing obstetricians now say. 

The fact that white women, on average, had better odds of a successful VBAC “represents the effects of systemic racism,” like disparities in income and access to good healthcare, says Darshali Vyas, MD, a resident physician at Massachusetts General Hospital. “It’s not anything intrinsic about being Black or brown.”

Knowing about the racial gap in VBAC outcomes might be vital information for improving the healthcare system. But some doctors say that whether an individual patient identifies as African American or Hispanic doesn’t help predict whether they are likely to end up with an emergency C-section. 

In a statement to Consumer Reports, the American College of Obstetricians and Gynecologists distanced itself from the “inappropriate incorporation of race as a biological risk factor” in tools like the VBAC calculator.

Public resistance to the use of race in the calculator began in 2019 when Vyas, then a medical student at Harvard, co-wrote a paper on the subject that was published in the journal Women’s Health Issues. Among other points, it argued that the choices offered—African American, Hispanic, or neither—were imprecise and unscientific, in part because a lot of people don’t clearly fall into a single category. That was Mockler’s situation. And other racial categories weren’t included at all; you couldn’t pick Asian, Native American, or white, for instance.

The tool risked making disparities in maternal healthcare even worse, the researchers concluded.

“As a baseline, total C-section deliveries are higher for Black women,” says Julianna Schantz–Dunn, MD, one of Vyas’ co-authors and medical director of ambulatory obstetrics at Brigham and Women’s Hospital. That could be because Black women are more likely to have preexisting conditions that make vaginal births riskier, doctors and midwives say, but also because they are less likely to be listened to by medical providers. Hispanic and Asian women have higher C-section rates than white women, too.

“Then if you have a calculator that nudges towards an automatic repeat C-section, you get into a circular problem, with disparities in C-section rates growing,” Schantz–Dunn says. That’s worrying because of the dangerous complications that can stem from C-sections, such as infections and internal bleeding.

The VBAC calculator alone shouldn’t determine a person’s chance of giving birth vaginally, researchers agree. Medical history and the hospital’s preparedness for VBACs should weigh heavily, too. But the risk scores can exert a strong influence on birthing options, several obstetricians and midwives told Consumer Reports. In some hospitals, the calculator is built straight into patient record systems.

In the end, Mockler ended up being transferred to a nearby hospital and delivering her second child, a son, by C-section, a procedure she doesn’t believe was necessary. The whole experience, including her encounter with the VBAC calculator, deepened her skepticism of medicine. “I’m Black, and I’ve had a lot of issues in the health system,” she says. “This experience makes me trust it less.”

A New Calculator Is Released

Though the VBAC calculator was updated last week, the change may take some time to reach providers around the country. The new version of the tool removes questions about race and ethnicity, and adds one new question that asks about the patient’s history of hypertension.

William Grobman, MD, a professor of obstetrics and gynecology at Northwestern University, was the lead researcher behind the original calculator, and he led the study, published this month in the American Journal of Obstetrics and Gynecology, that informed the update. “At the end of the day, if the calculator ends up solidifying a concept of race as biology or determinative of outcome, that’s a fundamental bad,” Grobman says. “The potential harms are so great that it’s something we need to studiously avoid.”

Critics of the old VBAC calculator applauded the update. “This is a powerful example of what equity work looks like in this space,” says Vyas. “It shows that tools can remain scientifically rigorous and accurate without race-correcting.”

But it didn’t need to take this long, she says. “We had evidence for several years that this tool did not need to use race,” she points out.

No one knows exactly how many Black or Hispanic women were needlessly steered away from a VBAC during the decade-plus that the race-adjusted calculator was in wide use. The best estimate comes from a recent study presented at a 2021 Society for Maternal-Fetal Medicine conference. The study examined the records of hundreds of women who attempted a VBAC at Boston Medical Center between 2017 and 2018. It found that Black and Hispanic women were significantly less likely than white women to have received favorable VBAC scores, defined as 60 percent or above.

Of the Black women in the study who had a VBAC, 44 percent had unfavorable scores when race was included, but only 12 percent had unfavorable scores when it wasn’t. And 45 percent of the Hispanic women in the study who had VBACs had unfavorable scores when race was included compared with 10 percent when it wasn’t.

Shakeela Faulkner, MD, the resident physician at Boston Medical Center who led the study, says the findings reinforced her discomfort with the race adjustments in the VBAC calculator. She’s happy to see them removed.

“If you had been white, you’d be more likely to be successful—it’s very hard to stand behind that statement,” Faulkner says.

Even as it’s removed from the VBAC calculator, race is still found in plenty of clinical algorithms and medical tests. Many of those tools are being reexamined, too.

Another domino fell earlier this year when two major kidney associations said they support removing race from a widely used kidney function test that systematically made Black patients’ kidneys look healthier than white patients’. Consumer Reports covered the push to reform the way that tool treated race last year.

If you’re considering trying for a VBAC, experts say it’s important to gather as much information as possible about your previous C-sections to help judge the risk. It’s appropriate to ask how your race figures into any of the advice your doctor is giving you, and to push back if you feel as if you’re being treated unfairly—or find another provider.

You can also do research on local hospitals to see which ones regularly perform VBACs. The Leapfrog Group, a nonprofit health advocacy organization, has a tool where you can see how hospitals rate on maternity care. An important factor in the ratings is whether a hospital has an acceptably low rate of C-sections.

It’s also useful to meet with doulas, midwives, or support groups who can help advocate for you. There’s a lot of strong evidence that the right birthing support can help reduce your likelihood of ending up with an unneeded C-section, and that doulas can be a particularly useful resource.

Editor’s Note: This article has been updated to clarify that a study led by Shakeela Faulkner, MD, was initially presented at a 2021 medical conference. The abstract of the study was then published in the American Journal of Obstetrics & Gynecology. The article was originally published on May 27, 2021.


Headshot of CRO author Kaveh Waddell

Kaveh Waddell

I'm an investigative journalist at CR's Digital Lab, covering algorithmic bias, misinformation, and technology-enabled abuses of power. In the past, I've reported for Axios and The Atlantic, and as a freelancer in Beirut. Outside work, I enjoy biking and hiking in and around San Francisco, where I live, and doing the crossword while cheating as little as possible. Find me on Twitter at @kavehwaddell.