May 29, 2024 - Health

Heat waves increase risk of early births, study finds

Maya Goldman

Illustration of a 3D health cross shape dripping and melting from heat. — Illustration: Aïda Amer/Axios

The rates of premature and early-term births slightly increase after heat waves, and the risk grows as extreme temperatures last longer, according to a new study of 25 years of birth data.

Why it matters: It's one way that extended heat waves, which have grown more common with climate change, may be harmful to infant health, the study in JAMA Network Open suggests.

Premature birth is the most common cause of death for infants and can lead to many long-lasting health challenges.

What they found: After four straight days of abnormally high temperatures, there's a 2% higher chance of babies being born prematurely (before 37 weeks). The chance is 1% higher for early-term births (37-38 weeks).

The risk was slightly higher among Black and Hispanic mothers and those with less education.
Researchers analyzed 53 million births during the spring and summer between 1993 and 2017 in the 50 most populous U.S. metropolitan areas.
Researchers said their study is the largest yet of the association between extreme heat and perinatal health.

Go deeper: Extreme heat's health consequences

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Heat waves increase risk of early births, study finds

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