Understanding Heat Exposure Risks During Pregnancy

Living Lab 2: Protecting Maternal Health in a Changing Mediterranean Climate

Pregnancy introduces unique physiological changes that make women more sensitive to extreme temperatures. As the Mediterranean experiences longer and more intense heatwaves, pregnant women face greater risks of dehydration, sleep disturbance, and heat stress, conditions that can influence both maternal and fetal health.

Evidence collected in Europe shows that prolonged heat exposure during pregnancy can lead to increased blood pressure at night, mental stress, and adverse birth outcomes such as preterm delivery or low birth weight. The Mediterranean region, identified by the Intergovernmental Panel on Climate Change as a climate-change hotspot, already records average temperature increases above the global mean, along with more frequent heatwaves and air-pollution events.

Living Lab 2 (LL2) of ISMED-CLIM specifically addresses this issue. It aims to generate clinical evidence on how timely, personalized recommendations can help pregnant women reduce their exposure to extreme heat and maintain healthy daily habits during warm periods.

Why Pregnant Women Are More Vulnerable

During pregnancy, the body’s ability to regulate temperature is reduced. Blood volume and heart rate increase, while metabolic heat production rises. High ambient temperatures can therefore cause dehydration and fatigue more quickly than in non-pregnant adults.

Scientific studies referenced in the ISMED-CLIM proposal highlight several physiological and behavioral effects linked to heat exposure:

  • Sleep disruption caused by elevated night-time temperatures, reducing total sleep time and sleep efficiency.

  • Increased blood pressure during the night, with a loss of the normal “dipping” pattern that supports cardiovascular recovery.

  • Dehydration and electrolyte imbalance, particularly during extended periods of outdoor activity or insufficient fluid intake.

  • Elevated stress hormone levels (cortisol), which can reduce blood flow to the placenta and influence fetal development.

These mechanisms show how climate-related heat stress can translate into real health risks — not only for the mother but also for the unborn child.

What the Living Lab Tests

LL2 operates in Catania (Italy) and Limassol (Cyprus). Each site recruits volunteer participants at different stages of pregnancy. The study divides them into two groups:

  • IG2 (Heat-Only) – focusing solely on heat-related recommendations.

  • IG3 (Heat + Air Quality) – combining heat-related and air-pollution-related advice.

Both groups receive a structured set of interventions during the warmer months, covering practical measures to manage heat and maintain comfort. The interventions are aligned with existing clinical guidance and tailored for the Mediterranean context.

Examples of recommended actions include:

  • Stay hydrated – drink water often, avoid alcohol or caffeine

  • Keep rooms cool – use fans or air-conditioning, stay indoors when it’s hot

  • Rest midday – avoid outdoor activity during peak heat hours

  • Seek shade – spend time in shaded or air-conditioned spaces

  • Wear light clothes – choose breathable fabrics to stay comfortable

  • Close curtains – block sunlight to reduce indoor heat

The study evaluates whether systematic communication of these measures, combined with environmental alerts, can lead to measurable improvements in behavior and physiological responses.

Monitoring and Data Collection

LL2 uses a controlled trial design. Participants are equipped with wearable sensors that measure body temperature, heart rate, and activity levels. Environmental data on temperature and air quality are collected in real time and matched with individual exposure data.

By comparing intervention and control groups, researchers will be able to assess:

  • How effective the interventions are in reducing actual exposure to heat and pollutants.

  • Whether the recommended behaviors translate into measurable health benefits, such as lower heart-rate variability under heat stress or improved sleep patterns.

  • How personal compliance changes when recommendations are provided in a timely and accessible format.

These findings will feed into the development of early-warning and response systems capable of protecting vulnerable populations, including pregnant women, during extreme heat events.

 

Towards Evidence-Based Prevention

The ultimate goal of LL2 is not only to validate individual recommendations but to provide quantitative evidence that can inform national and regional public-health policies. By demonstrating how simple preventive behaviors — hydration, cooling, and indoor heat control — can mitigate health risks, ISMED-CLIM contributes to a broader understanding of maternal health adaptation in a warming climate.

Findings from LL2 will also support the creation of regional guidelines for pregnancy care during heatwaves, helping healthcare professionals and public institutions across the Mediterranean integrate climate-sensitive measures into everyday practice.

As the project progresses, the results from the LL2 trials will inform future strategies for public-health preparedness, ensuring that maternal and neonatal care systems are ready to respond to increasing environmental stressors.