According to the best data available, as summarized in a report by the Centers for Disease Control and Prevention, the United States could prevent two-thirds of maternal deaths during or within a year of pregnancy.

Policies and practices to do so are well understood; we just haven’t employed them.

A first step is measuring maternal death rates, which is harder than you might think. The death needs to be directly related to the pregnancy or management of it, and confirming this requires careful data collection and assessment. Here is a straightforward example: A death because of inadequate care during delivery would count as a maternal death, and one because of a car accident after delivery would not.

But there are trickier cases.

Early this year, the CDC reported that in 2018, for every 100,000 live births, there were 17.4 maternal deaths. But this figure does not include maternal deaths from drug overdoses or suicide, so it may be an undercount.

Differences across groups

One statistic that we can be more certain of: There are large maternal mortality differences across racial and ethnic groups. The latest figures from the CDC indicate that for Black women, the maternal mortality rate is 37.1 deaths per 100,000 live births. It is less than half that, 14.7, for white women and less than one-third that, 11.8, for Hispanic women. There are also differences by region, with new mothers in rural areas facing greater threats to health than those in urban ones.

The best source of maternal mortality data comes from maternal mortality review committees, which now operate in all but a few states. They conduct case reviews to assess causes of maternal deaths.

When the CDC pulled together data from 14 such committees, spanning 2008-17, it also found wide variation in death rates by race and ethnicity. For example, although non-Hispanic white women make up about two-thirds of the U.S. female population, they account for only about half of maternal deaths. Non-Hispanic Black women, on the other hand, make up about 12% of that population but account for nearly 40% of maternal deaths.

The racial differences in maternal mortality are paralleled in racial differences in infant mortality. At 11.4 per 1,000 live births, the Black infant mortality rate is more than twice that of the white infant mortality rate, 4.9.

The racial differences seen in both maternal and infant mortality are driven by the same forces. Relative to white people, Black Americans have less access to the health system and receive poorer care, with worse outcomes. This has been documented both broadly and specifically for birth outcomes. Racism, including in its institutional and implicit forms, underlies all these factors.

Another way racism plays a role is before pregnancy.

“People of color experience the cumulative effects of disadvantages throughout their lives,” said Rachel Hardeman, an assistant professor with the University of Minnesota School of Public Health. “The constant stress of racism may lead to premature biological aging and poor health outcomes for African Americans. This means they might enter into pregnancy less healthy.”

Medicaid’s role

One-third of pregnancy-related mortality occurs after delivery. Lack of insurance imposes a financial barrier to postpartum care that might have prevented many of these deaths. In all states, low-income pregnant women — those with incomes below 133% of the federal poverty level, though most states have higher thresholds than 133 percent — are eligible for Medicaid, which finances over 40% of births nationally.

But a couple of months after delivery, new mothers can lose coverage, particularly in states that haven’t expanded the program. Among states that had not expanded Medicaid as of June 2018, the median threshold for eligibility for Medicaid as a parent was 43% of the federal poverty level. Texas and Alabama had the least generous parental Medicaid coverage, at 17 percent and 18 percent. Women of color are more likely than white women to be covered by Medicaid, so are more likely to be affected by postpartum eligibility changes.

Before the Affordable Care Act’s coverage expansion, 55% of women enrolled in Medicaid at the time of delivery experienced at least one month without insurance during the six months after delivery. Nowadays there is a big postpartum coverage difference depending on which state people live in. States that did not expand Medicaid have three times the postpartum uninsured rate of states that have expanded the program (22% vs. 7%).

“Medicaid has a positive impact on the health of low-income women, but for many, eligibility is limited to pregnancy and the immediate postpartum period,” said Sarah Gordon, an assistant professor at the Boston University School of Public Health who studies Medicaid policy. “The program could be even more powerful in alleviating racial disparities if coverage was longer term.”

In a study this year in Health Affairs, she and colleagues documented a connection between postpartum Medicaid coverage and care. The study found that in Colorado, which expanded Medicaid in 2014, mothers retained Medicaid coverage for longer and used more postpartum outpatient care compared with mothers in Utah, which did not expand Medicaid until after the study was conducted. Other work shows that expanded Medicaid is associated with a drop in infant mortality rates, echoing findings from earlier Medicaid expansions for pregnant women.

Coverage and care after delivery isn’t the only way to reduce maternal and infant mortality. Coverage and care before pregnancy and during the prenatal period certainly matter, too, as does the kind of care received during delivery. For example, a systematic review found that continuous, personal support during delivery can improve maternal and infant outcomes, including reducing the likelihood of a cesarean delivery.

Though the statistics may not be perfect, America’s maternal mortality rate is higher than it need be and disproportionately so for Black Americans and those in rural areas. The evidence suggests that targeted public health investments and policy changes like expanding Medicaid coverage could help.