A new study from scientists at the University of Cambridge has found that stressors like systemic racism and socioeconomic disadvantages may impact key processes in the body during pregnancy, which may explain the persistent disparities in maternal outcomes for Black women compared to White women.
In a major review of published studies on maternal outcomes, the study authors identified three key physiological mechanisms that impact pregnancy outcomes and show measurable differences between Black and White women. According to the review, the authors found Black women had increased uteroplacental vascular resistance, a tightening of blood vessels that can reduce blood flow to the placenta; higher oxidative stress, which can lead to lower levels of protective antioxidants; and greater inflammation, which can weaken the body’s immune response.
All of these biological outcomes are linked to higher rates of various pregnancy complications like pre-eclampsia, maternal hypertension, fetal growth restriction, and preterm birth. As these findings cannot be explained by genetic differences between Black and White women, the authors suggest these racial disparities are likely driven by socio-environmental stressors.
“Importantly, these physiological pathways are not genetically inherent. Rather, chronic exposure to persistent psychosocial stress can alter gene expression through epigenetic mechanisms,” the authors conclude. “Upstream exposures may also influence pregnancy outcomes through direct effects on physiological pathways that do not necessarily require gene-regulatory changes. The differences observed in this review are therefore more plausibly explained by the biological embedding of unequal stress exposures rather than by fixed genetic differences between Black and White women.”
