The Impact of Heat Exposure on Reduced Gestational Age in Pregnant Women in North Carolina, 2011–2015

Heat stress poses serious health risks to maternal health, including an increased probability of preterm labor and preterm birth. Yet the Southeastern US, where extreme heat exposure is high and maternal outcomes are some of the most challenging in the nation, has seen insufficient research and action on this issue.

Unlike previous studies that focus on the impacts of a single heat wave event, this study analyzed a 5-year period during North Carolina’s annual warm season (May–September). The results reveal significant impacts to pregnant women exposed to heat. The magnitude of this impact varies across regions, from a 1% increase in risk to 6% increase in risk per two-degree increment above established minimum temperature thresholds.

Understanding the impact of heat on preterm birth in the Southeast could help mitigate the increasing risk to pregnant women in a region predicted to have more extreme heat conditions, particularly increasing minimum temperatures. Examining the underlying vulnerability that contributes to heat impacts on pregnant women in this region and setting thresholds for levels of risk will be useful in developing prevention policies, such as early warning messaging and materials.