A Gap That Should Not Exist
Black and African American women in the United States die from pregnancy-related causes at rates far higher than white women. They experience preeclampsia (dangerous high blood pressure in pregnancy), preterm birth, and miscarriage more often. These are not small differences.
For too long, medicine attributed these gaps to biology alone — as if something inherent in race explained the disparity. That framing has been challenged, and this review helps explain why it is wrong.
Rethinking What Causes These Complications
The old view: racial health gaps in pregnancy are primarily explained by genetic differences between racial groups.
But here's the twist — race is largely a social category, not a biological one. Genetic ancestry and socially-defined race overlap but are not the same thing. Treating them as identical obscures what is actually happening. The real story is more nuanced and more urgent.
The Placenta as a Living Record
Think of the placenta as a logbook. Everything the mother experiences during pregnancy — the stress of housing insecurity, exposure to environmental pollutants, the chronic strain of discrimination — gets recorded in the placenta's biology.
This happens through a process called epigenetics: changes to how genes are turned on or off, without changing the DNA itself. Stress hormones, pollution, infections, and poor nutrition can all leave chemical marks on the placenta's genes. These marks influence how the placenta functions, how it nourishes the fetus, and whether complications develop.
What This Review Pulled Together
This review synthesized evidence from studies on placental biology, genetics, and epidemiology to understand how social and biological factors interact to produce pregnancy disparities. Researchers examined genome-wide association studies (large genetic surveys), placental epigenetic data, and electronic health records. They also explored how machine learning might improve pregnancy risk prediction when designed to be equitable.
What the Evidence Reveals
The review found that African-ancestry populations are significantly underrepresented in pregnancy genomics research. This means the genetic discoveries made in these studies apply less reliably to Black women — the very population most at risk. It is a gap that compounds the problem rather than solving it.
The review also confirmed that the placenta's immune function is particularly vulnerable to disruption by psychosocial stressors, environmental exposures, and infections — and that these disruptions fall disproportionately on Black women because of structural inequities, not personal choices.
This does not mean individual doctors are the cause — it means the systems and conditions that shape people's lives need to change too.
Why This Research Direction Matters
Understanding the placenta as a mediator of social inequity reframes how researchers and clinicians should approach high-risk pregnancies. Instead of looking only at biological factors in isolation, this framework asks: what has this woman experienced, and how has her biology responded? That shift could open doors to earlier identification of risk and more targeted support.
If you are pregnant or planning to become pregnant, especially if you are Black or of African ancestry, know that your risk for certain complications is real and documented — and that it reflects systemic factors, not a failure of your body. Ask your care team about early monitoring for preeclampsia and preterm birth risk. Seek out providers familiar with these disparities.
Limitations Worth Acknowledging
This is a review of existing evidence, not a clinical trial. It cannot prove causation. The gaps in genomic research it identifies mean that many of the biological mechanisms described are still being confirmed. Machine-learning tools for pregnancy risk prediction are still in early development.
Researchers are calling for more inclusive genomic studies that center African-ancestry populations, and for the development of AI-based risk tools that integrate biological data with social determinants of health. These tools could eventually help flag high-risk pregnancies earlier. But building them requires the kind of diverse, well-resourced datasets that science has so far failed to collect at scale.
