New Research Explores Links Between Pregnancy Factors and Autism

Immune System Activity During Pregnancy and Autism

Research suggests that when a pregnant person's immune system is highly active due to infections, inflammation, or autoimmune conditions, it may influence fetal brain development. A 2025 study in Molecular Psychiatry found that immune activation in pregnant primates led to lasting changes in brain regions involved in social behavior. These findings align with human studies showing connections between immune activity during pregnancy and later autism diagnoses.

Certain immune molecules present in the parent's blood during pregnancy and in umbilical cord blood at birth may help identify children who could benefit from early support, according to research from the Simons Foundation Autism Research Initiative. However, more research is needed before these findings can be used clinically.

A 2025 study in Molecular Psychiatry found that immune activation in pregnant primates led to lasting changes in brain regions involved in social behavior.

Environmental Factors During Pregnancy

Exposure to air pollution containing very small particles (known as PM2.5, which are 30 times thinner than a human hair) during late pregnancy has been associated with increased autism likelihood, as shown in a 2014 study. Other factors that may play a role include gestational diabetes, maternal obesity, and certain viral infections during pregnancy like COVID-19 (SFARI, 2023).

Practical Considerations and Next Steps

While these connections are becoming clearer, researchers note that predicting individual outcomes remains complex. A 2026 review highlights that the exact mechanisms are still being studied, and factors like the timing and intensity of immune system activity may be important.

For families concerned about environmental exposures, experts suggest practical steps like using air filters during high pollution days and discussing immune health with healthcare providers during pregnancy. However, it's important to note that autism is a natural variation in neurodevelopment with many contributing factors, and these findings don't imply causation.