How extreme heat is putting pregnancies at risk

May 2026 broke records as the hottest ever in the UK, as temperatures reached highs of 35.1°C.

These temperatures are not normal. They are a direct result of climate change.

With the UN warning that global temperatures could continue to rise by up to 2.8°C by the end of this century, the impacts of these changes on our health are becoming impossible to ignore.

While we are all feeling the effects of the heat, the most vulnerable are left without support. One of these groups is pregnant women.

How do rising temperatures affect pregnancies?

There is growing evidence that heat exposure during pregnancy significantly increases risks for both mothers and babies. It can increase the risk of preterm birth, miscarriages, still birth and complications for mothers such as preeclampsia.

When under heat stress, pregnant women can experience dehydration, difficulty sleeping, increased anxiety, dizziness and fainting, and lower blood pressure. 

A lack of public knowledge and healthcare advice around heat also mean that pregnant women are often unaware of the increased risks heat can pose or simply don’t know what to do in higher temperatures. Heat is not embedded in NHS maternity care guidelines, leading staff to rely on their own judgement when it comes to giving advice to pregnant women.

The problem is not just in hot countries

It’s important to note that this isn’t just a problem for people in countries experiencing high temperatures or heatwaves; it’s a problem anywhere where temperatures climb rapidly.

For example, a population used to an average summer temperature of 24°C may find temperatures of 30°C to 34°C physiologically stressful, even if those temperatures are considered normal in other places.

Both absolute heat and sudden deviations from local norms matter.

Heat stress is exacerbated by poor infrastructure

Our infrastructure in the UK is simply not adapted for the higher temperatures that climate change brings, which will only worsen the impacts on pregnancies.

Many homes lack the adaptations needed to keep cool during hotter weather, with half of UK homes already at risk of overheating and 92% of existing homes at risk of overheating by 2050.

On top of this, NHS buildings are often old, poorly insulated and without air conditioning or cooling systems. During the 2022 heatwave, temperatures exceeding 40°C caused outages of data centres serving hospitals in London.

This particularly affects the delivery of babies. As body temperatures spike during childbirth naturally, it becomes difficult to pinpoint whether the cause of an increased temperature or heart rate is a result of an issue like infection or sepsis or simply overheating.

Vulnerable groups are worst affected

The burden of extreme heat disproportionately falls on vulnerable groups, including pregnant women and those living in deprived areas.

Someone living in a poorly insulated home with no outdoor space is going to find it harder to follow advice about staying cool than someone living in a well-insulated home with a shaded garden.

On top of this, pregnant women who work physically demanding jobs or who are reliant on public transport are often not able to lessen their workload or take respite from the heat during extreme temperatures.

The solutions exist

Despite growing recognition that heat threatens maternal and newborn health, there has been a lack of practical action thus far. But the solutions exist.

Lessons from the Global South

Across the Global South, progress has already been made.

In Africa, where populations have been living with heat for centuries, sophisticated adaption techniques have already been developed.

Evaporative cooling systems, passive ventilation, shading systems, tree planting, local architecture, airflow design and local materials are used alongside modern technologies to deal with heat. These interventions have been proven to reduce miscarriages in pregnant women.

In Zimbabwe, community health workers are being trained in preventative care and heat health so that they can properly advise pregnant women on how best to care for themselves and their baby in higher temperatures.

Adapting to local needs, rather than importing expensive solutions that may be difficult to maintain, is key.

What can we do to protect pregnancies from climate change?

There are some key actions we can take to reduce the impact of rising temperatures on pregnant women.

1. Climate and heat considerations must be made in healthcare and hospitals.

Whether it’s retrofitting buildings to ensure they can deal with higher temperatures or training healthcare staff on how to best help pregnant women during heatwaves, it is key that we make sure our health systems are ready for climate change.

2. Government health guidance for pregnant women must be updated.

All existing government health guidance for pregnant women and new mothers must be updated to reflect rising temperatures and include advice on what to do in a heatwave to keep babies and mothers safe.

3. Adverse weather plans and alert systems must include pregnant women.

Existing heat thresholds should be reviewed, and any adverse weather plans or alter systems must take the vulnerabilities of pregnant women into account.

4. The Healthy Homes standard must be updated to include better climate resilience.

Better insulation, air conditioning and less reliance on fossil fuels must be included in Healthy Homes requirements to ensure homes are ready for the impacts of climate change.

The impacts of climate change are already happening and will continue to impact our health in the years to come. With action, we can shield the most vulnerable from the worst effects and ensure pregnancies are protected.