In utero air pollution exposure and pre- and postnatal brain development: a review

Area of Science:

• Environmental Health
• Neuroscience
• Public Health

Background:

• Air pollution poses a global public health threat, potentially impacting brain development during sensitive prenatal and childhood windows.
• The developing brain is vulnerable to environmental influences, with prenatal exposure to air pollutants possibly disrupting neurodevelopmental processes.

Purpose of the Study:

• To review evidence from ultrasound and MRI studies on the association between prenatal air pollution exposure and structural brain development from fetal life through adolescence.
• To evaluate the effects of specific air pollutants, including particulate matter (PM), nitrogen oxides (NOx), and others, on fetal and childhood brain structure.

Main Methods:

• Literature review of ultrasound and MRI studies examining in utero exposure to various air pollutants (PM10, PM2.5, NOx, SO2, CO, black carbon, O3).
• Summarized findings per pollutant to assess individual pollutant effects within complex air pollution mixtures.
• Analyzed associations with global fetal brain metrics (biparietal diameter, head circumference) and regional brain structures (cerebral cortex, gray/white matter).

Main Results:

• Evidence indicates associations between prenatal air pollution exposure and altered structural brain development.
• Prenatal ultrasound studies in high-pollution areas showed negative associations with fetal head size metrics.
• Childhood MRI studies in lower-exposure areas found no global volume changes but reported alterations in regional brain structures, potentially affecting cognitive outcomes.

Conclusions:

• Current evidence supports a link between prenatal air pollution exposure and altered brain development.
• No distinct patterns or differences were identified between individual pollutants.
• Further longitudinal and mechanistic studies are needed to confirm causal pathways and functional consequences.