Maternal prenatal co-exposure to air pollution and psychological distress shapes the neonatal gut: microbiota-mediated pathways to early neurodevelopment.

Three distinct maternal prenatal air pollution-psychological distress co-exposure patterns were identified using a self-organizing map (SOM) among 309 mother-infant pairs.

• 309 mother-infant pairs were recruited from obstetrics departments of two tertiary hospitals.
• The self-organizing map approach was used to identify co-exposure patterns combining air pollution and psychological distress data.
• Both general environmental exposures (air pollution) and specific psychological exposures (psychological distress) were measured during pregnancy.

Meconium microbiota composition differed among the three co-exposure patterns at both the phylum and genus levels.

• Meconium samples were collected within 48 hours after birth.
• Differential features of meconium microbiota in relation to co-exposure patterns were assessed using multivariate association of linear models (MaAsLin).
• Differences were observed at both the phylum and genus taxonomic levels across the three co-exposure patterns.

Ruminococcus mediated the relationship between maternal prenatal co-exposure patterns and infant neurodevelopment at 3 months of age.

• The indirect effect (IE) of Ruminococcus as a mediator ranged from 0.181 to 0.261.
• The mediation effect was statistically significant at pFDR < 0.001.
• Infant neurodevelopmental outcomes were assessed using the Ages and Stages Questionnaire-3 (ASQ-3) at 1, 3, and 6 months postpartum.
• The mediating role was specifically identified at the 3-month postpartum assessment time point.

Infant neurodevelopmental outcomes were longitudinally assessed at multiple postpartum time points using a standardized instrument.

• The Ages and Stages Questionnaire-3 (ASQ-3) was used to assess neurodevelopmental outcomes.
• Assessments were conducted at 1, 3, and 6 months postpartum.
• Mediation analysis was used to analyze the role of meconium microbiota in linking co-exposure patterns to neurodevelopmental outcomes.

The study supports inclusion of infant gut microbiota within risk assessment frameworks for maternal prenatal environmental and psychological co-exposures.

• The findings provide a scientific basis for identifying intervention targets for high-risk populations.
• Air pollution is characterized as a 'general' external exposure and psychological distress as a 'specific' external exposure during pregnancy.
• The joint influence of air pollution and psychological distress on early life gut microbiota had not previously been explored prior to this study.