Extreme Heat Raising Risks For Pregnant Women And Newborns, New Report Warns

Surging global temperatures are creating new and serious risks for pregnant women and newborns, according to a report released by the Wellcome Trust and related research projects. Health professionals across several countries are reporting an increase in heat-related pregnancy complications, while early studies link higher ambient temperatures to more preterm births and stillbirths.

What The Report Found

The Wellcome Trust survey of 1,000 doctors and midwives across Australia, Brazil, Britain, India and Zimbabwe found that 73% of clinicians have observed an increase in heat-related problems during pregnancy and childbirth. More than a quarter of those surveyed reported that fewer pregnant women seek care during heat waves, a problem particularly acute in low-income settings where patients often travel to clinics on foot.

How Heat Affects Pregnancy And Newborns

• Reduced Placental Blood Flow: High ambient temperatures cause superficial blood vessels to dilate, which in pregnant women can substantially reduce blood flow to the placenta and lower oxygen and nutrient delivery to the fetus. This is associated with higher risks of stillbirth, premature delivery and low birth weight.
• Newborn Thermoregulation: Newborns have limited ability to regulate body temperature. Heat stress can impair breathing and make breastfeeding more difficult, increasing the risk of early complications.
• Maternal Cardiovascular Strain: Extreme heat places heavy demands on the maternal cardiovascular system and can indirectly raise the risk of gestational diabetes, severe hypertension and pre-eclampsia.
• Access To Care: Heat waves reduce access to prenatal and perinatal services, particularly in regions where transportation is limited or patients travel by foot.

Supporting Research And Context

A Wellcome-funded study in Wales, called MAGENTA, has linked prolonged exposure to temperatures above 25°C with increased rates of preterm birth and stillbirth. Early findings suggest that each 1°C rise in heat exposure is associated with roughly a 5% increase in the risk of preterm birth.

Climate context: August 2026 was the warmest August on record, with an average global surface air temperature of 16.96°C — about 1.65°C above pre-industrial levels. The UK experienced its hottest summer on record the same year, with five separate heatwaves over a 40-day span and temperatures reaching as high as 38°C in some areas.

Global Health Implications

The World Health Organization identifies climate change as the greatest threat to global public health. Between 2030 and 2050, climate change is projected to contribute to an additional 250,000 deaths per year, driven mainly by heat stress, malnutrition and the spread of infectious diseases into newly hospitable regions.

Dr Madeline Thomson, Head of Climate Impacts and Adaptation at Wellcome, said: "Extreme heat, fuelled by climate change, is impacting our way of life and our health — and yet many countries are not prepared. With El Niño pushing temperatures higher, the failure to act is costing lives. We already know many of the solutions to protect people — from early warning systems to cooler buildings — but the challenge is delivering those solutions to the people who need them most, including pregnant women and newborns."

Practical Steps: Policymakers and health services can reduce risk by expanding heat-health warning systems, ensuring cooling options in health facilities, adapting prenatal-care scheduling during heat waves, and providing targeted guidance for pregnant women on hydration, shade, and when to seek urgent care.