How Rising Heat Waves Endanger Pregnant Women: Understanding the Growing Health Risks and Impacts

Heat can significantly exacerbate anxiety, depression, and feelings of isolation, both during pregnancy and after childbirth.

Medical professionals have established that heat places considerable strain on vital organs including the heart and kidneys. These risks become particularly pronounced for pregnant individuals, as their body's natural cooling mechanisms undergo substantial alterations.

This issue is being intensified by climate change, resulting from fossil fuel combustion including gasoline and coal. The increasing frequency of extreme heat events, elevated nighttime temperatures, and record-breaking weather patterns are causing greater heat exposure for pregnant people, with developing nations experiencing disproportionate impacts.

Here's essential information about the scientific relationship between pregnancy and extreme heat:

Pregnancy transforms the body in numerous ways, which can compromise its ability to dissipate heat effectively and comfortably.

"One obvious factor is that pregnant individuals develop a belly bump, depending on their gestational stage, which alters their surface-to-volume ratio," explained Anna Bershteyn, associate professor at New York University's Grossman School of Medicine and director of Project HEATWAVE, an initiative focused on improving research into preventing heat-related mortality. Heat escapes through the skin, and as the abdomen enlarges, heat must travel a greater distance to dissipate.

As pregnancy progresses, metabolic rate increases, generating more internal heat. The cardiovascular system works harder, potentially compounding strain already caused by high temperatures. Additionally, pregnant individuals require increased fluid intake for hydration, making them more susceptible to dehydration, according to the Environmental Protection Agency.

One cooling mechanism involves redirecting blood flow toward the skin and away from central organs, causing the skin to flush red when overheated. Emerging research suggests that reduced blood circulation to the placenta can impact fetal development.

For pregnant individuals handling potent chemicals like pesticides, increased blood flow can enhance chemical absorption, noted Dr. Chris Holstege, chief of medical toxicology at the University of Virginia School of Medicine.

Research is beginning to demonstrate that extreme heat exposure, even in pre-conception months, may impact future pregnancies, according to Cara Schulte, a researcher with the University of California, Berkeley and Climate Rights International, who studies maternal health and heat effects.

During pregnancy, even brief heat exposure can elevate the risk of severe maternal complications, including pregnancy-induced hypertensive disorders, as reported by the EPA. This includes potentially fatal conditions like preeclampsia that threaten both mother and child.

Heat can also worsen psychological conditions such as anxiety and depression, and postpartum, "these challenges are compounded by the difficulties new mothers face in caring for their infants during hot weather," Schulte observed.

As they develop, children exposed to extreme heat in utero may face increased developmental challenges throughout their lives, potentially linked to adverse outcomes such as preterm birth or low birth weight, according to Schulte.

"This remains a significantly understudied area," Bershteyn noted, adding that much current knowledge derives from studies involving athletes, military personnel, or physically fit young individuals. "Women's health research hasn't received comparable investigative commitment."