- Posted
- May 31, 2024
Studies find link between heat waves, preterm births
Heat waves are becoming more frequent and more intense around the world, and several studies have identified an increased risk of preterm delivery and stillbirth after heat exposure (Source: “Heat waves associated with increased risk of preterm birth in the U.S.,” Stat News, May 28).
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. Its results shed light on the way existing health inequities may be exacerbated by a worsening climate.
The study found that after a heat wave, which the study defined as four consecutive days in which the mean temperature was higher than the local 97.5th percentile, preterm births increased by 2%, and early births by 1%. But the distribution of these adverse outcomes was uneven: Mothers who were 29 or younger, had a lower level of education, and belonged to a minority ethnic or racial group saw a 4% increase in preterm births, and a 3% increase in early deliveries.
Several recent studies have also found strong links between high temperature and adverse pregnancy outcomes. A study published last May in the Lancet based on data from eight Chinese provinces found that the rates of preterm birth could have been reduced by about 15% had pregnant women been warned to protect themselves from impending extreme heat. Another study published in April found that the risk of miscarriage was double among women in the Indian state of Tamil Nadu who had high occupational heat exposure. They also experienced double the risk of adverse outcomes at birth.