Here’s How Extreme Heat is Hurting Pregnant Women

Sustained extreme heat events are increasingly affecting vulnerable pregnant populations. As global warming becomes more severe, scientists are noting increases in birth complications, including early births and underweight infants.

Extreme heat during the day, and especially warm nights that do not sufficiently cool off from daytime temperatures, are particularly problematic. Between 2011 and 2015, Ashley Ward, senior policy associate at the Nicholas Institute, and her coauthors, found that the risk of preterm birth rose by up to 6% with every two-degree increase in temperatures exceeding 75°F between May and September.

“What we might be seeing is an inability to recover from exposure during the day,” Ward told National Geographic. “We’re having increasingly warmer nights, and that’s where we should be concerned.”