From warming skies to premature birth: environmental heat reprograms placental function

Pregnant women face a significant risk of adverse birth outcomes when exposed to heatwaves or elevated environmental temperatures, especially during the critical windows of early and late gestation. Although the danger is clear, the biological mechanisms driving heat-induced premature birth remain poorly understood. Could maternal heat exposure reprogramme the gene expression and epigenetic architecture of the placenta—the vital organ that maintains pregnancy and supports foetal growth—thereby undermining its function? And what evidence do we really have that climate change is reshaping the physiology of the female reproductive system? In this article, we present solid evidence from human tissues and experimental models, alongside conceptual insights, to illuminate how heat stress alters placental biology in ways that can lead to preterm birth—the primary cause of neonatal and under-five childhood mortality worldwide.