Faced with increasingly frequent heatwaves and their dramatic consequences for the health of the most vulnerable, four UN agencies are joining forces. They are launching the very first set of priority indicators to help states monitor, anticipate and counter the impacts of global warming on pregnant women, newborns and children.

As global temperatures reach worrying highs, the climate emergency is taking on a critical medical dimension for the most fragile populations. The World Health Organization (WHO), the World Meteorological Organization (Omm), Unicef and the Fnuap officially launched, on 21 October, an unprecedented global framework aimed at measuring precisely the effects of extreme heat on maternal and child health. The scientific evidence is now conclusive: high temperatures do not just cause discomfort, they kill and seriously damage health from the earliest age. Prolonged exposure to extreme temperatures increases the risk of premature birth by 26%.

The figures are just as alarming for early childhood. In 2024, infants under one year old experienced 389% more heatwave days compared with the 1986-2005 period. Across the planet, nearly 1.5 billion children face increasingly frequent, long and intense heatwaves.

Until now, health systems have suffered from a glaring lack of targeted data to act effectively. “Heat is already affecting our most vulnerable populations, but health systems cannot respond to what they do not count,” warns Dr Pascale Allotey, Director of the Department of Sexual, Reproductive, Maternal and Child Health at the WHO.

To fill this gap, the new UN report recommends that governments impose rigorous monitoring on the ground. The authorities will now have to cross-reference meteorological data (air temperature) with specific health indicators: premature births and stillbirths; low birth weight; pregnancy-related high blood pressure; mortality rates and paediatric emergencies; and school attendance during heat peaks.

Prevent rather than endure

The ultimate aim is to enable states to move from reaction to anticipation. By identifying health anomalies during heatwaves, hospitals will be able to prepare their departments for surges in patient numbers, strengthen alerts aimed at pregnant women and prioritise the most exposed communities.

In the face of this reality, the WHO urges all countries to urgently integrate the health of mothers and children into their national heat and climate action plans. In an inexorably warming world, gathering reliable scientific data remains the last line of defence against foreseeable human tragedies.