How do seasons and high temperatures affect pregnancy and birth outcomes in England?
Background
Pregnancy is a particularly sensitive period during which mother and child are vulnerable to environmental conditions. Previous research suggests that pregnancy and birth outcomes can vary by season and that exposure to high temperatures, as well as air pollution, may affect the health of mothers and infants. However, we still do not fully understand these patterns across England, how they have changed over time, or whether some families may be more vulnerable than others.
What will we do?
We will use data from the Kids Environment and Health Cohort (KEHC), a large national study of children born in England from 2006 to 2022, which allows us to link information about children’s health over time with information about where they live and their local environment, including temperature, air quality, housing characteristics and neighbourhood quality.
First, we will investigate seasonal patterns in stillbirth, birth weight, the proportion of babies born male or female, and deaths around the time of birth. We will examine whether these patterns differ by certain characteristics; for example, whether the mothers were born in the UK or elsewhere, or by their ethnicity. We will examine differences by housing and neighbourhood characteristics, such as neighbourhood deprivation or whether families live in urban or rural areas.
Second, we will investigate whether exposure to high temperatures during pregnancy is associated with stillbirth and whether male and female infants may be affected differently. We will consider different measures of heat exposure, such as heatwaves, high temperature shortly before delivery, and the number of unusually hot days during late pregnancy. We will also investigate whether associations differ according to maternal and neighbourhood characteristics that may make some communities more vulnerable to heat.
Why is this important?
Climate change is increasing the frequency and intensity of hot weather. Understanding which periods of pregnancy and which communities may be particularly vulnerable could help inform public health advice and policy-planning.
Funding
This study is funded by The Wellcome Trust.
