Extreme Heat Linked to Preterm Births Surge
Pregnant people in heat-exposed areas face higher risk of early delivery during heat waves.
Updated on Nov. 7, 2026 in Pregnancy
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A Zero Carbon Analytics estimate links 15 days of extreme heat in the Philippines in April 2024 to 585 additional preterm births. The analysis also estimates 263 of those preterm births would not have occurred without human-induced warming, and it covered pregnancy outcomes in the Philippines, India, and Bangladesh.
Why it matters
Preterm birth is a leading cause of death among children under 5 worldwide, so heat-driven increases in early delivery carry serious health stakes for pregnant people and newborns. The World Health Organization has now included preterm birth in a new framework for tracking heat-related impacts on pregnancy, newborns, and children.
Zero Carbon Analytics compared observed heat conditions in April 2024 with normal temperatures to estimate excess preterm births across the Philippines, India, and Bangladesh. The figures are estimates from this analysis rather than a controlled clinical study.
The players
Zero Carbon Analytics
A climate research group that produced the analysis estimating heat-linked preterm births.
World Health Organization
The United Nations health agency that identifies preterm birth as a leading cause of death among children under 5 and has added it to a new heat-impact tracking framework.
Climate Change Commission
The Philippine government body that cautioned about projected extreme temperatures during this year's Super El Niño.
The details
Extreme heat can push pregnant people's bodies toward thermal stress, which the analysis associates with earlier delivery. In the April 2024 heat wave, the heat index in Iba, Zambales peaked at 127.4 F (53 C), and regional estimates included about 100 additional births in Calabarzon and about 80 each in Metropolitan Manila and Central Luzon. The researchers attribute the excess births to heat conditions made more likely by human-caused climate change.
Timeline
April 2024: 15 days of extreme heat occurred in the Philippines.
This year (2026): The Climate Change Commission cautioned that a Super El Niño could push some city temperatures to 45 to 50 C.
Health Landscape
The WHO's new framework creates a formal way to monitor how heat affects pregnancy and early childhood health. This study adds a country-level estimate of preterm births tied to a single heat wave, a measure the framework is positioned to track over time.
Pregnant people in regions facing extreme heat may benefit from discussing heat exposure and prenatal care plans with their clinician. Staying hydrated and limiting time in peak heat is a practical habit worth raising with a doctor or midwife.
The takeaway
Extreme heat is increasingly linked to preterm birth, a major driver of child mortality. Pregnant people should ask their care provider how to manage heat exposure during hot periods.
Further reading
For more on maternal and newborn health, explore our Pregnancy coverage.
Source note: This article includes information reported by The Cool Down.
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