Exposure to air pollution during early pregnancy may impair infants’ language and motor development, according to a new study. The researchers found that babies exposed to higher pollution levels in the first trimester scored on average 5–7 points lower on language tests at 18 months than those with lower exposure.
The study followed 498 infants in Greater London. Stronger effects were observed among babies born prematurely. In this group, higher pollution exposure during pregnancy was associated with significantly poorer motor skills, with scores on average 11 points lower.
The pollutants analysed—fine particulate matter and nitrogen dioxide—mainly originate from traffic emissions. Using detailed modelling, researchers estimated exposure levels based on mothers’ home addresses during pregnancy.
Importantly, pollution levels in the study were within current legal limits in the UK, but above the stricter guideline values recommended by the WHO. The findings add to growing evidence that air pollution can affect brain development from the earliest stages of life, raising concerns that current standards may not be sufficiently protective.
The authors emphasise the need for further research to determine whether these developmental differences persist into later childhood, but argue that reducing exposure during pregnancy should be a public health priority.
Source: Kings College London 29 April 2026 https://www.kcl.ac.uk/news/air-pollution-exposure-in-the-womb-linked-to-worse-language-and-motor-development
