Scorching Risks: How Extreme Heat from Climate Change Endangers Pregnant Women and Their Babies

As climate change continues to drive up global temperatures, the toll on human health is becoming increasingly clear. Among those most at risk? Pregnant women and their unborn children. Extreme heat is more than just uncomfortable—it’s a silent threat that can trigger severe complications during pregnancy and impact fetal development in lasting ways.

Heatwaves are surging—along with pregnancy risks

A recent analysis by Climate Central found that between 2020 and 2024, the number of “heat-risk days” during pregnancy—defined as days with temperatures hotter than 95% of the historical norm—doubled across 222 countries. These spikes in heat days are especially prevalent in regions already struggling with limited health care access, such as parts of the Caribbean, Central and South America, and sub-Saharan Africa.

But the United States is not immune. From California to the Gulf Coast, extreme weather is making pregnancy harder and more dangerous, especially for marginalized communities who face the brunt of rising temperatures and unequal access to care.

Why pregnancy makes heat more dangerous

According to Dr. Shruthi Mahalingaiah of the Harvard T.H. Chan School of Public Health, pregnant individuals are less able to regulate body temperature—not just for themselves, but for the developing fetus. “The body is already undergoing profound physiological changes,” she explains. “And keeping the fetal environment at a safe temperature becomes even more challenging during heatwaves.”

This impaired ability to cool down can lead to serious complications such as gestational diabetes, pre-eclampsia, and even organ damage. A recent study warns that these changes can increase hospitalizations and put both mother and child at elevated risk.

Extreme heat can harm fetal development

What’s especially alarming is the impact on babies in the womb. Since a fetus cannot regulate its own temperature, excessive maternal heat exposure has been linked to neural tube defects, low birth weight, and developmental delays. Some studies even suggest that extreme temperatures during key developmental windows may raise the risk of congenital abnormalities.

A 2024 study published in JAMA Network Open found that preterm and early-term births rose significantly in areas experiencing prolonged heat spikes. Preterm infants often face lifelong health issues, ranging from respiratory and neurological disorders to higher rates of infant mortality.

It’s not just the body—climate change disrupts reproductive care, too

Climate-related heat can also compromise access to reproductive health tools. Items like pregnancy tests and certain types of birth control become less reliable or entirely ineffective when exposed to high temperatures. According to MSI Reproductive Choices, over 11 million women in 26 countries have had their access to contraception disrupted due to climate-related displacement and supply chain issues.

Extreme heat, poor infrastructure, and climate disasters like floods or hurricanes can also limit access to clinics and hospitals, delaying critical care. In fact, a 2023 report by climate risk firm XDI found that climate change has increased the threat of damage to hospitals by 41% globally. And that damage has ripple effects—just ask New Yorkers who saw maternity wards disrupted during Hurricane Sandy.

Marginalized communities face the greatest danger

As with so many health risks, climate change magnifies existing inequalities. Low-income families and communities of color are less likely to have access to air conditioning, quality health care, or even safe housing—making them far more vulnerable during heat events. Those living near highways or industrial zones are also exposed to higher levels of pollution, which further compounds pregnancy complications.

Air pollution—another byproduct of our warming planet—has been linked to high blood pressure during pregnancy, restricted fetal growth, and lower birth weights, according to the World Health Organization. Meanwhile, natural disasters can spike stress, contaminate the environment, and cut off access to prenatal care—each of which may trigger early labor or worse.

We still don’t know enough—but we know enough to act

Experts agree: we’ve only scratched the surface when it comes to understanding how climate change is impacting maternal health and fetal development. But the evidence we do have is sobering. “We need to think holistically about both the upstream and downstream effects of climate change across the reproductive life cycle,” says Dr. Mahalingaiah.

Whether it’s protecting vulnerable families from extreme temperatures, improving access to resilient health care, or integrating climate science into OB-GYN training, the time to act is now. As a doctor told us, “This is not a far-off issue. It’s happening now, and it’s putting mothers and babies at risk.”