Heat exposure during pregnancy, early childhood may affect brain development, new study find

A young girl holds her baby sister as they walk among water jets to cool down inside a park in central Athens on Thursday July 12, 2012. (AP Photo/Dimitri Messinis)

Heat may have lasting effects on brain development for children, a new study suggests.

According to research published in the Environment International journal, exposure to high temperatures during the early stages of life, including pregnancy, is linked to slower growth of the thalamus – a region in the brain involved in processing information – later in childhood.

The study, first published online in June, was led by researchers from the Barcelona Institute for Global Health (ISGlobal).

Experts say the brain develops rapidly during pregnancy and the first years of life, making it especially sensitive to environmental factors. The findings raise concerns about the impact of extreme temperatures on children’s health as a result of climate change, according to the report.

“With global temperatures continuing to rise, measures to reduce heat exposure during pregnancy and early infancy could play an important role in protecting children’s brain development,” Mònica Guxens, a co-ordinator of the study and a research professor at ISGlobal, said in a press release shared by the institute Monday.

The study examined more than 3,200 children from the Netherlands’ Generation R research project, a population-based prospective cohort study. According to Laura Granés, a researcher and co-author of the study, researchers obtained weekly estimates of outdoor temperatures during pregnancy, as well as monthly estimates of temperatures from birth to eight-and-a-half years of age at each child’s residence.

“We wanted to examine whether exposure to heat or cold from conception to 8.5 years of age was associated with changes in brain development during late childhood and adolescence, and to identify the periods when the brain is most vulnerable,” Granés said in the press release.

Researchers later analyzed two separate MRI scans of participants conducted at 10 and 14 years of age, allowing them to measure the volume of 11 brain structures over time and determine whether they were linked to earlier exposure of heat or cold, she added.

What part of the brain was impacted?

Researchers found that the thalamus was the only region in the brain that consistently showed a connection with heat exposure during early life, according to the press release. They believe this region is especially sensitive, since it develops in early pregnancy and has a rich blood supply.

The thalamus processes and transmits sensory and motor information to the cerebral cortex, the biggest region of the brain with a key role in information processing.