(STAT News) – Heat waves are becoming more frequent and more intense, posing more of a health risk around the world. High temperatures can be deadly, and are especially dangerous for those with cardiovascular and chronic disease — but they begin affecting human lives even before birth.

Several studies have identified an increased risk of preterm delivery and stillbirth after heat exposure around the world. A new investigation, published on Friday in JAMA Network Open, confirmed the link to early deliveries at a massive scale, in a large cohort study capturing over half of the births that occurred in the United States between 1993 and 2017. (Read More)