2024 heatwave linked to 585 more preterm births in Philippines — study

MANILA, Philippines — Nearly 600 more babies were born too early in the Philippines during the April 2024 heatwave, a new study estimates, as the country heads into another stretch of extreme heat under a strong El Niño.

Zero Carbon Analytics, an international think tank on climate change and the energy transition, estimates an additional 585 babies were born preterm during the 15-day extreme heat event, a 10% increase above average April figures.

The World Health Organization (WHO) defines "preterm births" as those occurring before 37 weeks.

Temperatures during the 15-day spell ran 2.44 degrees Celsius above normal. At its peak, the town of Iba, Zambales logged a heat index of 53 degrees Celsius, one of the highest readings of the year at the time.  

Climate change, according to the organization, caused the pre-monsoon weather to be 1.2 degrees hotter, leading to a separate estimate of 263 preterm births that would not have occurred without human-caused warming.

Zero Carbon Analytics compared the Philippines' statistics for April 2024 to the country's average April based on data from 1991 to 2020, following a baseline established by the World Meteorological Organization. Results were reported at a 95% confidence level.

Calabarzon saw the highest nominal increase at 100 births, closely followed by Metro Manila and Central Luzon with around 80 births each.

Cagayan Valley, however, had the highest rise in risk: Cagayan province experienced temperatures 4.01 degrees hotter than normal, resulting in a 17% surge.

Babies born too early are more prone to breathing problems, infections, difficulty feeding and trouble keeping warm, according to the WHO.

Complications of preterm birth are the leading cause of death among children under five worldwide, and many survivors live with lifelong disabilities.

A nation at risk

The Philippines was ranked seventh in Germanwatch's Climate Risk Index, meaning that heat-specific exposure is rising faster in the country than in most parts of the world.

Between 2020 and 2024, the country experienced 36 days with maximum temperatures above a threshold linked to increased preterm birth risk. Climate change is thought to be responsible for 30 of these days, given that a 1-degree increase in temperature is associated with 4% higher odds of preterm birth. 

Women and newborns living in poverty are especially vulnerable due to limited access to healthcare, mobility, and resources to support traditional livelihoods.

The Climate Change Commission warned that temperatures could reach 45 to 50 degrees in treeless urban areas during Super El Niño, which began in October 2026. The weather pattern is expected to last until March 2027 and has already brought drought conditions to various provinces in the country.