London is a key part of the MAGENTA project, offering a way to understand how heat exposure during pregnancy may affect mothers and babies in a large and diverse urban population.

The MAGENTA team at University College London (UCL) is leading the analysis of data for London using the Kids’ Environment and Health Cohort (KEHC), which combines national birth records with environmental data.  With over 1.1 million births included, the rich dataset reflects the diversity of London’s population, which means the research can explore how heat exposure during pregnancy may affect outcomes and whether some groups are more affected than others.

London’s built environment, with dense urban areas, buildings and roads, can trap heat, so temperatures often stay higher than in surrounding areas – this is known as the urban heat island effect, and it can increase exposure during warmer periods.

London is also expected to see some of the greatest increases in temperature in the UK in the coming years. Combined with the urban heat island effect, this makes it an important place to understand how rising temperatures may affect health, particularly for those already more vulnerable to heat.

But temperature is not experienced in the same way across the city, with housing quality, overcrowding, and access to green space all affecting indoor and outdoor temperatures – these factors are closely linked to wider inequalities, which the team at MAGENTA aims to understand in greater detail.

The UCL team is also interested in how different environmental exposures may act together. In cities like London, because of the urban heat island effect, high temperatures often coincide with higher levels of air pollution. Housing quality and access to green space may help to offset some of these effects. By examining these combined exposures, researchers can begin to understand how the design of communities and even specific homes may shape people’s exposure to heat.

As well as London, the MAGENTA team is working with data from Wales, where environmental conditions are quite different. By combining environmental modelling with linked health data from both London and Wales, MAGENTA will build a clearer picture of how heat exposure during pregnancy affects outcomes, and whether risks vary between populations and places.

Professor Pia Hardelid said, “London gives us a way to look at heat exposure in a large and diverse urban population, and to explore how it may affect different groups during pregnancy.”

Dr Amal Rammah added, “Using KEHC, we can link health and environmental data at scale and understand how housing, neighbourhoods and other factors may shape exposures to heat and pregnancy outcomes.”

Prof Mario Cortina Borja said, “Advanced statistical modelling allows us to identify seasonal patterns that aren’t immediately visible, allowing to quantify how heat exposure at different stages of pregnancy influences outcomes.”

This work will add to the evidence on how climate-related risks affect maternal and child health and help inform future research and public health planning.