Women who breathe wildfire smoke during pregnancy, especially in late stages, may put their offspring at greater risk of autism. These are the findings of a new study of California births published January 20 in the journal ‘Environmental Science & Technology’.

Researchers found that exposure during the third trimester, when the fetus’ brain grows rapidly, was linked to a higher chance of an autism diagnosis in childhood.

The study looked at health records from more than 200,000 births between 2006 and 2014 in Southern California, a region with both frequent wildfires and higher autism diagnosis rates.

Autism, or Autism Spectrum Disorder (ASD), is a lifelong neurodevelopmental condition affecting social communication, interaction, and behaviour, characterised by diverse strengths and challenges, ranging from difficulties with social cues and repetitive actions (like hand-flapping) to intense focused interests and sensory sensitivities, with the “spectrum” meaning its presentation varies widely.