Extreme Heat & Climate Change and Pregnancy Risk
Climate change is driving an alarming rise in extreme heat events worldwide — heatwaves are becoming more frequent, longer, and more intense.
Pregnant women are among the most vulnerable to these changes because pregnancy naturally increases body temperature, blood flow, and heart rate.
Recent studies (2024–2025) have found that exposure to extreme heat during pregnancy is linked to serious risks for both mother and baby, including preterm birth, stillbirth, gestational hypertension, and low birth weight.
Pregnancy Increases Sensitivity to Heat
During pregnancy, a woman’s body:
- Produces more metabolic heat.
- Has expanded blood volume and cardiac workload.
- Experiences hormonal changes that alter thermoregulation.
- Often retains more body fluid, increasing risk of dehydration in heat.
This makes it harder for the body to cool down, so external heat adds dangerous stress to maternal organs and the developing fetus.
Major Health Risks Linked to Extreme Heat
1. Preterm Birth & Early Labour
- Heat exposure (especially in the last trimester) increases uterine contractions.
- Studies show a 16–20% higher risk of preterm delivery during heatwaves.
- Mechanism: Heat causes dehydration → oxytocin release → early contractions.
2. Stillbirth
- High temperatures (especially >35–38°C) have been directly associated with increased stillbirth risk.
- A global review in 2024 estimated a 5–10% increase in stillbirth risk for every 1°C rise in temperature during the third trimester.
3. Gestational Hypertension & Preeclampsia
- Heat stress can raise blood pressure and strain the cardiovascular system.
- It can worsen fluid retention and trigger endothelial damage, leading to hypertensive disorders of pregnancy.
4. Dehydration & Reduced Amniotic Fluid
- Intense heat leads to fluid loss, thickened blood, and reduced placental perfusion.
- This affects nutrient and oxygen supply to the fetus, increasing risks of low birth weight and fetal distress.
5. Maternal Exhaustion & Heat Stroke
- Heat stroke during pregnancy can be life-threatening for both mother and baby.
- Symptoms like dizziness, rapid heartbeat, nausea, and confusion are dangerous warning signs.
How Climate Change Exacerbates These Risks
- Rising Global Temperatures: The last decade has been the hottest on record, and 2025 is tracking toward another record-high year.
- Increased “Pregnancy Heat-Risk Days”: ClimateCentral (2025) found that in some countries, the number of extremely hot days during pregnancy has doubled in five years.
- Urban Heat Islands: Cities amplify heat stress due to concrete, pollution, and poor air circulation — urban pregnant women face the highest exposure.
- Poor Air Quality: Climate change worsens air pollution and wildfire smoke, compounding the respiratory and cardiovascular stress during pregnancy.
- Socioeconomic Disparities: Low-income and rural women often lack access to cooling, hydration, or healthcare during heatwaves.
Global Findings
- India: Reports show heatwaves in northern and central India are linked to a notable rise in preterm births and maternal hospital admissions.
- U.S. & Europe: New data indicate that 20–30% of heat-related maternal admissions are preventable with cooling interventions.
- Africa & Southeast Asia: Pregnant women in these regions face the highest risk due to limited air conditioning, poor hydration, and lower healthcare access.
Expert Insights
“Pregnancy already challenges the cardiovascular and renal systems — extreme heat adds further stress that can tip the balance toward complications.”
— Dr. Sonja Rasmussen, University of Florida (2025)
“Climate change is no longer an abstract future threat — it’s a daily risk for pregnant women, especially in low-resource countries.”
— World Health Organization, 2025 Report on Maternal Health & Environment
Preventive Measures & Adaptation Strategies
For Pregnant Women:
- Hydration: Drink water frequently, even before feeling thirsty.
- Avoid Peak Heat: Stay indoors or in shaded/cool areas between 10 a.m. and 4 p.m.
- Wear Light Clothing: Loose, breathable cotton fabrics help regulate body temperature.
- Monitor Symptoms: Report dizziness, headache, swelling, or contractions early.
- Rest Often: Avoid overexertion, especially in the third trimester.
For Healthcare Providers:
- Screen for heat-exposure risk during prenatal visits.
- Educate patients on recognizing heat exhaustion symptoms.
- Ensure cooling facilities and hydration support in maternity wards.
- Integrate weather alerts into maternal care programs.
For Policymakers:
- Develop “Heat Action Plans” targeting pregnant women and newborns.
- Improve access to community cooling centers.
- Include maternal health in climate resilience and disaster management frameworks.
Conclusion
Climate change has turned heat into a silent maternal health crisis.
Extreme temperatures now pose direct biological, environmental, and social threats to pregnant women and their babies.
Protecting maternal health means treating heat not just as weather, but as a medical emergency — requiring awareness, prevention, and stronger public health action.