New Delhi, June 13 : Maternal exposure to pollution, particularly during the second and third trimesters of pregnancy, can affect specific brain structures of unborn babies in the womb, according to a study.

The study, published in The Lancet Planetary Health, showed that the changes were linked to brain imbalances, loss of motor coordination, and slow development.

"During mid to late gestation, the foetal brain enters a key phase of its development, making it particularly vulnerable to external factors such as pollution," Payam Dadvand, a researcher at Barcelona Institute for Global Health (ISGlobal) in Spain.

"As clinicians, we are now seeing compelling evidence that even in pregnancies that appear healthy by all conventional measures, factors such as air pollution can subtly affect foetal brain development," added Elisa Llurba and Lola Gómez-Roig, clinicians at the Hospital de Sant Pau and BCNatal-Hospital Sant Joan de Déu, respectively.

For the study, the researchers analysed data collected between 2018 and 2021 from 754 mother-foetus pairs.

A specialised ultrasound that allows the analysis of foetal brain shape and structures -- transvaginal neurosonography -- during the third trimester showed that prenatal exposure to nitrogen dioxide (NO'), particulate matter (PM2.5), and black carbon led to an increase in the volume of various brain cavities that contain cerebrospinal fluid.

Specifically, direct associations were identified between exposure to these pollutants and increased volume of the lateral ventricles, located in each brain hemisphere, as well as an enlargement of the cisterna magna, a cavity located at the lower part of the brain.

An increase in the width of the cerebellar vermis -- the central part of the cerebellum, essential for balance and motor coordination -- was also detected.

The results also suggested less maturation of the brain.

"The point is that these differences, although small at the individual level, are indeed relevant from a population perspective, as they inform us about how pollution affects the foetal brain and its vulnerability to environmental exposures," said Laura Gómez-Herrera, ISGlobal researcher.

The researchers emphasised the need for further studies to confirm the findings and stressed the need for increased awareness and education, both within the health community and across society.

/IANS