Moms in America are more likely to die during or shortly after childbirth compared to mothers in any other developed country. When you start to drill into that grim statistic, though, one thing becomes strikingly clear: It’s largely African American women who are dying.

Black moms across the US are three and a half times more likely to die in childbirth than white Americans. (The pregnancy-related mortality rate is 12 per 100,000 live births for white women, and 40 per 100,000 for black women.)

That gap is also growing:

Remarkably, though, North Carolina has managed to close its black-white maternal death gap. In 1999, 39 black women per 100,000 live births died as a result of pregnancy-related complications compared to only 11 white women per 100,000 in the state. By 2013, the gap closed: The rate was 23 per 100,000 births for both white and black moms, bringing North Carolina about on par with the national maternal mortality rate.

Alarmingly, the white maternal mortality rate has risen in North Carolina over the years. Health officials there aren’t sure what’s going on yet, but told me they plan to investigate. And the trend mirrors a uptick nationwide in white mortality that’s been linked to opioid abuse, and increases in obesity, diabetes, and cardiovascular disease.

Still, the black maternal death rate in North Carolina has halved, and the gap between black and white deaths has closed. You simply don’t see this kind of convergence in the area of maternal mortality anywhere else in the US. Even in California, which has managed to drive down its maternal death rate to only 7.3 deaths per 100,000 — the lowest in the country — the black-white health gap remains stubbornly persistent. (As of 2013, seven white women per 100,000 births died and 26 black women per 100,000 births died — in line with the national disparity.)

What’s unique about North Carolina, according to doctors, nurses, and researchers there, is a population health management program, called Pregnancy Medical Home, for low-income pregnant women. The program is run through Medicaid, the government health insurance for the poor, and 94 percent of Medicaid doctors participate in the program. And it’s just one of several initiatives in the state to make births safer for moms that seem to be saving more lives.

Why North Carolina may be seeing its racial health gap disappear

When a woman on Medicaid in North Carolina becomes pregnant, her doctor is incentivized (through Medicaid financial reimbursements) to screen for issues that might make her pregnancy high-risk, looking out for potential obstetric or psychosocial risks as early as possible, such as high blood pressure, diabetes, or depression. If the patient is deemed to be high risk, she’s connected with a “pregnancy care manager,” who helps the mom understand and adhere to steps needed to reduce her health risks.

Kate Berrien, the vice president of clinical programs at Community Care of North Carolina, walked me through how this works: Say a mom is identified as being at risk for preeclampsia, pregnancy-induced high blood pressure, which can be deadly for mom and baby. The mom’s doctor might suggest she start on low-dose aspirin, an evidence-based intervention to reduce the risk of preeclampsia.

“The doctor would let the pregnancy care manager know that the patient has been started on aspirin,” Berrien explained, “so that the care manager can follow up to make sure the patient is able to obtain the medication and that she understands how and when to take it, as well as why she is on this treatment.”

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If the mom has diabetes — one of the conditions that puts women at a higher risk of preeclampsia — the doctor might design a special diet for the patient. The care manager would then make sure the patient can actually follow the doctor’s recommendations (helping her with access to healthy food, offering support to adjust her diet, or frequent check-ins to assess her progress). The care manager might also help the mom access insulin, if necessary.

And if the patient isn’t responding to these interventions, and needs to be induced for an early labor to prevent complications to the mother and infant, the health care manager might help her get ready for her stay in the hospital, by finding a caretaker for her other children or making sure her family has access to the food they need while she’s out.

“That care manager will visit women at the doctor’s office or at the home,” said Kathryn Menard, director of maternal-fetal medicine at the University of North Carolina. “[She or he will] help mothers overcome any barriers in adhering to a care plan — like food insecurity, housing issues, access to insulin.” She continued: “I am not familiar with any statewide program like this.”

The primary goal of the program is pre-term birth prevention, Berrien added. “By tackling women’s health problems before she goes into labor, we mitigate her risks.”

Since the program launched in 2011, the state has also seen a decline in the C-section rate among Medicaid recipients and improvements in the low birth weight rate among babies.

“I believe this program really helps with our health care inequities that exist,” said Menard. “If you can help people navigate through the system and they’ve got peers in their community helping with care management — that makes a difference.”

Why the effort isn’t saving more white women’s lives isn’t clear. But African American women are disproportionately represented in the North Carolina Medicaid population and it’s possible that the Pregnancy Medical Home program for the Medicaid population might disproportionately benefit them, Berrien said.

Other explanations for why North Carolina’s black maternal mortality rate dipped

There’s no clear line of causation linking the change in North Carolina’s black maternal mortality rate and their unique Pregnancy Medical Home approach — the program just happened to be the one things that came up again and again when I asked people working in this area about what North Carolina was doing differently. What’s more, Pregnancy Medical Home launched in 2011, after which the black maternal mortality rate continued to decline — but it can’t account for the decline in the mortality rate among black moms before then.

And it’s possible there are other contributors to the decrease in death. The Perinatal Quality Collaborative of North Carolina launched in 2009 to improve mom and baby care across the state. They’ve worked in 65 birthing hospitals in North Carolina and conducted nine statewide quality improvement efforts, including reducing early elective deliveries, which can lead to deadly complications for moms and babies, and improving the management of preeclampsia.

“Gestational hypertension and preeclampsia are severe problems in the African American maternal population,” said Martin McCaffrey, a professor of pediatrics at UNC Chapel Hill School of Medicine who directors the program, in an email. “We have increased treatment of mothers with critical hypertension in less than an hour from 50 percent to 80 percent.” So it’s possible that this effort contributed, too.

The US has an serious black-white maternal death gap

One reason it’s so hard to parse what’s going on in North Carolina is that there’s no one, clear explanation for why black mothers across the country die from pregnancy complications at higher rates than white moms either. Bill Callaghan, the head of maternal and infant health at the Center for Chronic Disease Prevention in the CDC, believes it’s probably the result of a combination of factors, including:

Stress: “The experience of being African American in the US confers a different level of chronic stress from the beginning of life all the way through the life course,” he said, “and that can change how one’s body reacts to any physical stress in life, including the physical stress in pregnancy.” High levels of stress can exacerbate high blood pressure and heart disease, which can lead to deadly health complications during pregnancy.

Pregnant African Americans get different — and often worse — care than their white counterparts in hospitals, and that may be more likely to lead to pregnancy-related complications.

There are also underlying health differences in black versus white populations: heart disease, high blood pressure, and diabetes are more common among African Americans, and they can all contribute to pregnancy-related complications.

Black Americans generally have lower incomes than white Americans, which also means they may face more barriers in access to care and therefore worse maternity care. If moms don’t have adequate maternity care throughout their pregnancy, that means health care professionals may be less likely to intervene early on potentially deadly complications.

Other states are also tackling maternal death — to great success

The North Carolina Pregnancy Medical Home program is unique because it uses Medicaid as a tool to identify and address lifestyle-related factors early in the pregnancy that might make pregnancy more dangerous for moms and babies.

But other states are trying hospital-based interventions — and having great successes.

One outstanding example is California. As of 2013, there were 7.3 deaths per 100,000 in California — bringing the Golden State in line with countries like the United Kingdom or Portugal. That’s also half of what the state’s maternal death rate was in 2006, and a third of the national rate.

There, a group of doctors, nurses, midwives, and hospital administrators, started the California Maternal Quality Care Collaborative, an initiative to make births safer for moms in the state. Unlike North Carolina, their program is mainly focused on interventions in the hospital. They’ve designed “toolkits,” which are essentially evidence-based, step-by-step recipes — downloadable for free — on how teams of health care providers can best prepare for and manage the sometimes-deadly complications that arise with childbirth.

For example, one toolkit focuses on maternal hemorrhage, one of the leading causes of death for women in childbirth. One key idea in the hemorrhage toolkit was to make sure hospitals have all the best protocols and necessary tools that might save those moms’ lives in the event of a bleed. The toolkit recommends that every hospital delivering babies has a cart filled with everything needed to manage a hemorrhage and keep moms alive: medicines that slow the flow of blood, instruments that repair a tear or laceration, intrauterine balloons that can provide pressure and control bleeding from a uterus that isn’t contracting well. They did this after realizing many hospitals don’t have these tools ready, and a woman can bleed to death in five minutes after a childbirth, so minutes count.

If other states followed these recipes, we might see a drop in the national mortality rate like the one California has seen. But the clinical complications CMQCC has focused on so far are being outpaced by lifestyle-related health issues, like cardiovascular disease and opioid addiction. To address those issues, North Carolina may have some answers.

Update: We’ve added some context and clarification to this piece in response to reader feedback, especially this blog post at Andrewgelman.com.