Extreme heat is now a measurable health risk for mothers and babies, not just a summer discomfort. On 21 October 2026, WHO, WMO, UNICEF and UNFPA launched the first global priority indicators to help countries track how heat affects pregnant women, newborns and children. For the SRHR community, it is a long-overdue step in making maternal and child health visible in climate planning.

The scale of the risk

Heat exposure is linked to a 26% rise in the odds of preterm birth. Babies under one lived through 389% more heatwave days in 2024 than in the 1986–2005 baseline. About 1.5 billion children face heatwaves that are more frequent, longer or more severe. The latest Lancet Countdown report confirms the trend. Global heatwave exposure fell from the 2024 record, but 2025 was still the second-highest year on record for infants and older adults combined. 

What the research shows

Evidence from many settings points the same way. A Sydney cohort of more than 1.2 million births found a higher risk of preterm birth after extreme daytime and nighttime heat in the third trimester, and a New South Wales study found the risk rose on very hot days, especially for women with diabetes, hypertension or chronic illness. A 14-country analysis of more than 100,000 births found that extreme heat in the final week before birth raised the risk of preterm birth and stillbirth, with the authors warning that low- and middle-income countries often lack the infrastructure to cope. In Asia, a new Zero Carbon Analytics analysis finds that human-driven climate change is increasing preterm births across South and Southeast Asia and projects the burden to mid-century.

The mechanism is not fully settled. Researchers suggest heat stress may impair placental development or alter blood flow to the uterus, which could trigger early labour. Infants add their own vulnerability: they absorb heat quickly, and they cannot signal thirst or move to shade, so they depend entirely on caregivers.

What the new framework asks of countries

The framework asks health systems to read routine data alongside heat data. Recommended measures include preterm births, stillbirths, low birthweight, pregnancy hypertension, child deaths and facility visits during extreme heat. School attendance is also suggested, as a signal of how heat disrupts children’s lives.

It contains 19 indicators in total. Six test whether governments are following through, for example whether local health authorities receive heat early warnings. The indicators do not prove cause and effect. They are meant as a practical starting point for spotting trends and informing action. 

The need is clear. A 2025 WHO-commissioned review of 83 heat-health action plans from 24 countries found only 52% named pregnant women as an at-risk group, 39% named newborns and 14% named postpartum or breastfeeding women. 

Why this is an SRHR issue

Heat shapes access to care and the quality of care. Women may keep doors and windows closed for safety, which can trap heat indoors, disrupt sleep and raise stress. Care quality can also fall during extreme heat, as health workers report exhaustion and reduced pace. Midwives and community health workers are well placed to give clear risk information and help women reduce exposure.

Sources:

1. https://www.who.int/news/item/21-10-2026-new-global-framework-launched-to-track-increasing-health-risks-of-extreme-heat-for-pregnant-women–newborns-and-children 
2. https://healthpolicy-watch.news/who-launches-global-indicators-extreme-heat-maternal-newborn-health/
3. https://www.uniindia.com/national/climate-change-preterm-births/233438 
4. https://internationalmidwives.org/extreme-heat-is-putting-maternal-newborn-and-child-health-at-risk/ 
5. https://www.reuters.com/sustainability/how-heat-storms-threaten-pregnant-women-worldwide-2026-10-30/