Why are black mothers and babies dying? It’s unlikely to be weathering.

Racism, discrimination, prejudice and social exclusion message

A piece that will appear in The New York Times Sunday Magazine attempts to answer the question Why America’s Black Mothers and Babies Are in a Life-or-Death Crisis. Unfortunately, the answer it gives — that black women’s health is uniquely “weathered” by racism — while intuitively appealing, is probably wrong.

The tl;dr answer can be summarized as follows:

While racism is hardly limited to African Americans (think Native Americans nearly wiped out in a de facto genocide) the high rates of maternal and neonatal mortality are nearly exclusive to those of African descent.

And though the attention to the tremendous discrepancy in black vs white mortality rates has focused on the US, the problem is the same or worse for women of African descent in other countries.

Let’s look closer at the NYTimes piece and the existing research.

Linda Villarosa clearly lays out the problem:

Black infants in America are now more than twice as likely to die as white infants — 11.3 per 1,000 black babies, compared with 4.9 per 1,000 white babies, according to the most recent government data — a racial disparity that is actually wider than in 1850, 15 years before the end of slavery, when most black women were considered chattel. In one year, that racial gap adds up to more than 4,000 lost black babies. Education and income offer little protection. In fact, a black woman with an advanced degree is more likely to lose her baby than a white woman with less than an eighth-grade education.

This tragedy of black infant mortality is intimately intertwined with another tragedy: a crisis of death and near death in black mothers themselves. The United States is one of only 13 countries in the world where the rate of maternal mortality — the death of a woman related to pregnancy or childbirth up to a year after the end of pregnancy — is now worse than it was 25 years ago. Each year, an estimated 700 to 900 maternal deaths occur in the United States. In addition, the C.D.C. reports more than 50,000 potentially preventable near-deaths, like Landrum’s, per year — a number that rose nearly 200 percent from 1993 to 2014, the last year for which statistics are available. Black women are three to four times as likely to die from pregnancy-related causes than their white counterparts, according to the C.D.C. — a disproportionate rate that is higher than that of Mexico, where nearly half the population lives in poverty — and as with infants, the high numbers for black women drive the national numbers.

What explains the disparity? The causes could be genetic, environmental or both. Villarosa favors an environmental explanation.

Dr. Arline Geronimus, a professor in the department of health behavior and health education at the University of Michigan School of Public Health, first linked stress and black infant mortality with her theory of “weathering.” She believed that a kind of toxic stress triggered the premature deterioration of the bodies of African-American women as a consequence of repeated exposure to a climate of discrimination and insults. The weathering of the mother’s body, she theorized, could lead to poor pregnancy outcomes, including the death of her infant.

That’s an extraordinary claim and it falls apart fairly quickly when extended beyond black women.

If “weathering” were an accurate explanation of the black/white disparity in mortality, we would expect to find evidence of it in other populations exposed to racism. But that’s not what we find at all.

This graph comes from the 2017 paper Pregnancy-Related Mortality in the United States, 2011–2013.

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As you can see, black maternal mortality dramatically exceeds white maternal mortality. But if the weathering theory were true, we would expect that other ethnic groups would also experience weathering and that’s not what happens. One might argue that discrimination against African Americans is worse than discrimination against other ethnic groups but it’s simply not possible to argue that there is no discrimination against Hispanics. Nevertheless, maternal mortality statistics for Hispanic women are better than those of anyone else including white women.

The mortality discrepancy extends to other countries, too. The UK Confidential Enquiries into Maternal Deaths and Morbidity 2013–15 shows that maternal deaths of black women is 4X higher in the UK; that’s a greater discrepancy than the US.

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The situation is similar for perinatal mortality:

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One of the strongest pieces of evidence in favor of the weathering theory is that black pregnancy outcomes get far worse as women get older. According to the theory, the effect of discrimination and insults is cumulative. Therefore, the disparity gets greater as women get older. If that were the case, though, we should see widening disparities in deaths rates as women get older and that’s not what we find. The disparity actually decreases as women get older.

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White women born in 2015 are expected to live for 81.1 years, Hispanic women for 3.2 years more and black women for 3 years less. In contrast, among women who turned 65 in 2015, white women had a further life expectancy of 20.5 years, Hispanic women an additional 2.2 years more and black women only 0.9 years less. Similarly, for women who turned 75 in 2015, white women had an additional life expectancy of 12.9 years, Hispanic women an additional 1.8 years more and black women only 0.2 years less.

Obviously the best way to test the weathering hypothesis would be to look at maternal and neonatal mortality rates in countries where black people make up the majority of the population and are governed by other black people. Such countries are in sub-Saharan Africa and they have the worst maternal and perinatal mortality rates in the world as illustrated by this map of maternal mortality from the WHO.

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There are a myriad of factors that result in high maternal and perinatal mortality in Africa so it’s impossible to blame race. Nonetheless, it means that if race is a specific risk factor for genetic reasons, it is hidden behind the socio-economic problems of the continent.

Racial discrimination undoubtedly plays a role in high rates of maternal and infant mortality but there are other groups that face considerable racial discrimination and they don’t have comparably poor mortality rates. Moreover, women of African descent have higher mortality rates regardless of where they live; indeed, the driver of maternal and perinatal mortality rates in industrialized countries is the percentage of women of African descent in the population.

Although Villarosa, the author of the NYTimes piece, implies that genetic factors have been ruled out, that’s hardly the case. Scientists and physicians are loath to invoke genetics when it comes to racial differences and there are good reasons to be wary. Nonethess, we know that there are certain genetic mutations that conferred benefit on African populations (like the mutation for sickle cell anemia that was protective against endemic malaria) that now, in the absence of malaria, only confer harm. It would be a tragedy if we failed to look for such explanations for high black maternal and perinatal mortality and fell back on environmental explanations that are more intuitively appealing but could very well be wrong.