New York, NY — Doctors have long known that extreme heat can strain the heart, kidneys, and other organs, but recent research shows that pregnant people face even greater risks. As climate change intensifies, rising temperatures and longer heatwaves are creating dangerous conditions that threaten both maternal and fetal health worldwide.
Experts say that climate change, driven largely by the burning of fossil fuels like gasoline and coal, is increasing the frequency and duration of heat events. That means more pregnant individuals are being exposed to extreme temperatures — especially in developing countries, where access to cooling and healthcare is limited.
Why Pregnancy Makes Heat Harder to Handle
Pregnancy triggers a number of physiological changes that make it harder for the body to regulate temperature.
“An obvious thing is, pregnant people have a belly bump, depending how far along they are, and that’s a change in their surface-to-volume ratio,” said Anna Bershteyn, associate professor at New York University’s Grossman School of Medicine and director of Project HEATWAVE, a research initiative focused on extreme heat prevention. “Heat leaves your body through your skin, so when the belly gets larger, the heat has farther to travel to escape.”
As pregnancy progresses, the body burns more calories, producing additional internal heat. The heart works harder, which can be further strained during high temperatures. Pregnant people also require more hydration to stay cool, increasing their risk of dehydration when exposed to heat, according to the Environmental Protection Agency (EPA).
One of the body’s main cooling mechanisms — redirecting blood toward the skin — can also reduce placental blood flow, potentially affecting fetal development.
For pregnant people exposed to pesticides or industrial chemicals, the increased blood flow may also heighten toxin absorption, explained Dr. Chris Holstege, chief of medical toxicology at the University of Virginia School of Medicine.
Heat Risks Before, During, and After Pregnancy
Emerging studies suggest that heat exposure before conception can influence fertility and early pregnancy outcomes.
“Exposure to extreme heat even in the months before getting pregnant may affect a future pregnancy,” said Cara Schulte, a researcher at the University of California, Berkeley and Climate Rights International, which studies maternal health and climate impacts.
During pregnancy, even short-term exposure to heat may increase the risk of high blood pressure disorders, such as preeclampsia, which can be life-threatening for both mother and child, according to the EPA.
“Heat can also worsen anxiety, depression, and feelings of isolation,” Schulte added. “Once the baby is born, all of those things are compounded by the difficulty that postpartum women have in caring for their children in the heat.”
According to AOL News, children exposed to heat in utero may also face developmental challenges, such as low birth weight or preterm birth, which can affect health outcomes for years.
A Call for More Research on Women’s Health
Experts say the link between heat exposure and maternal health remains understudied, leaving major gaps in understanding.
“This is a hugely understudied thing,” said Bershteyn. “There hasn’t been the same level of commitment to women’s health research.”
Much of what is currently known about heat tolerance, she added, comes from studies on athletes, soldiers, and healthy young men, not pregnant individuals.
With global temperatures continuing to rise, researchers warn that protecting pregnant people from heat must become a public health priority — including access to cooling centers, early medical intervention, and heat safety education.
What do you think about the growing risks of heat exposure during pregnancy? Share your thoughts in the comments below.
