Pesticide exposure induces risks of gestational anemia by maternal gut microbiota: A prospective cohort study

Gut microbiota regulates host hematopoiesis, with notable alterations observed in individuals with gestational anemia (GA). Pregnancy-induced susceptibility to environmental stressors, including widespread pesticide residuals, may disrupt gut microbiota, further contributing to the development of GA. This study sought to investigate population-level associations between pesticide exposure and GA, with a focus on the mediating role of gut microbiota. Pregnant women were prospectively recruited with blood and stool samples collected in the second trimester. Red blood cell (RBC) count and hemoglobin (Hb) were assessed in the second and third trimesters. GA was diagnosed in 22.7 % of participants during the second trimester and 29.8 % during the third trimester. Robust associations were found between serum pesticides, such as atrazine and clomazone, and an increased risk of GA and reduced Hb and RBC count, both at a single time point and longitudinally. Pesticide exposure was linked to altered microbial Shannon index, with 24 significant associations identified between pesticides and individual taxa, nearly half of which involved Roseburia. Furthermore, both Shannon index and the Firmicutes/Bacteroidetes (F/B) ratio were negatively associated with RBC count. A total of 20 taxa showed associations with GA and hematological parameters. Finally, mediation analysis demonstrated that Shannon index and Roseburia mediated the relationships of pesticide exposure with RBC count and GA, respectively. These findings not only highlight the anemia-inducing effects of pesticides, but also inform microbiota-based interventions for managing GA and maternal health.