Extreme Heat Linked to Hundreds of Preterm Births
Pregnant people in hot regions face higher preterm birth risk during extreme heat, according to a new Philippine estimate.
Updated on Nov. 7, 2026 in Pregnancy
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Zero Carbon Analytics estimated that 15 days of extreme heat in the Philippines in April 2024 were linked to 585 additional preterm births. The analysis also covered pregnancy outcomes in India and Bangladesh, and found that 263 Philippine preterm births that month would not have occurred without human-induced warming.
Why it matters
For pregnant people and families, the findings tie prolonged extreme heat to premature birth, a condition the World Health Organization lists as a leading cause of death among children under 5. The WHO has now added preterm birth to its new framework for tracking heat-related impacts on pregnant people, newborns, and children.
Calabarzon recorded about 100 additional births linked to the heat, while Metropolitan Manila and Central Luzon each recorded about 80. The Climate Change Commission cautioned that temperatures in some cities could reach 113 to 122 F (45 to 50 C) during this year's Super El Niño.
The players
World Health Organization
The United Nations agency that sets global health standards and tracks threats to maternal and child health, and which has added preterm birth to its new heat-impact tracking framework.
Zero Carbon Analytics
A climate research group whose analysis estimated the preterm births linked to the April 2024 Philippine heat wave.
Climate Change Commission
The Philippine government body that advises on climate policy and warned of extreme temperatures during the Super El Niño.
The details
Zero Carbon Analytics analyzed pregnancy outcomes in the Philippines, India, and Bangladesh. The estimate worked by comparing observed heat conditions during the April 2024 heat wave to normal temperatures, then quantifying the preterm births associated with the excess heat. The analysis attributes the excess births to human-caused climate change.
Timeline
April 2024: 15 days of extreme heat occurred in the Philippines, linked to 585 additional preterm births.
2026: The Climate Change Commission warned of possible city temperatures of 45 to 50 C during this year's Super El Niño.
The Home Front
The WHO's new framework for tracking heat-related impacts on pregnant people, newborns, and children now explicitly includes preterm birth. This places a quantified heat-to-premature-birth estimate inside a global monitoring system rather than a one-off study.
If you are pregnant or planning a pregnancy during hot months, ask your midwife or obstetric provider how to keep cool and hydrated, and watch for heat-related warning signs. Keeping a cooling plan in place for hot spells, including access to shade, fans, and fluids, is a practical step to discuss with your care team.
The takeaway
Extreme heat is now being measured as a direct contributor to preterm birth, and the WHO is building it into global tracking. Families expecting a baby in hot conditions should plan cooling and hydration with their healthcare provider ahead of heat waves.
Further reading
For more on how pregnancy health is affected by conditions like heat, explore our Pregnancy section.
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