Heat-Risk Days for Pregnant People Have Doubled Worldwide Over Last 5 Years
A new report from Climate Central, a nonprofit news organization that analyzes climate science, showcases how the climate crisis has contributed to a growing risk for pregnant people around the world.
According to the report, the number of pregnancy heat-risk days — defined as days that are hotter than 95 percent of local temperatures recorded from 1991 to 2020 — has doubled across the globe over the past five years.
Increases were seen in 222 out of 247 countries and territories that were measured during the period 2020-2024, the analysis found. In a third of those areas (78 countries and territories), “climate change added at least one additional month’s worth of pregnancy heat-risk days on average,” the report noted.
“Human-caused climate change almost doubled the national average annual number of pregnancy heat-risk days in the U.S., compared to a world without climate change,” the report showed, finding that, over the past five years, 12 of the 25 annual pregnancy heat-risk days in the U.S. were due to the climate crisis.
All 50 states now experience at least an additional week’s worth of pregnancy heat-risk days each year compared to five years ago.
“Cities across the U.S. Southwest had the highest average number of pregnancy heat-risk days added by climate change,” the report said. Puerto Rico saw an 88 percent increase in heat-risk days for pregnant people, while Hawaii — which typically had only one heat-risk day five years ago — now sees 21 days of heat risk, on average.
“Even a single day of extreme heat can raise the risk of serious pregnancy complications,” read a statement from Climate Central’s vice president of science Kristina Dahl. “Climate change is increasing extreme heat and stacking the odds against healthy pregnancies worldwide, especially in places where care is already hard to access.”
Other examinations of exposure to extreme heat while pregnant demonstrate how serious these complications can be.
“Some studies have suggested that heat exposures in the first trimester, when the major organs form, could contribute to certain birth defects, whereas exposure in the second or third trimester, when the fetus undergoes rapid growth, may contribute to preterm birth or stillbirth,” as well as possibly “contribute to low birth weight,” explained a report written by independent journalist Lindsey Konkel, published on the National Institutes of Health website in 2019.
Speaking to ABC News about the report’s findings, Bruce Bekkar, a women’s health physician whose work focuses on the effects of the climate crisis, said that “extreme heat is now one of the most pressing threats to pregnant people worldwide, pushing more pregnancies into high-risk territory, especially in places already struggling with limited health care access.”
The Climate Central report further noted that other adverse weather events that are becoming more prevalent due to the climate crisis — including extreme flooding, wildfires, damage to infrastructure, and more — can also “increase risks for pregnant people.”
“Cutting fossil fuel emissions isn’t just good for the planet — it’s a crucial step toward protecting pregnant people and newborns around the world,” Bekkar added.