Prenatal Pyrethroid Exposure, Placental Gene Network Modules, and Neonatal Neurobehavior

Prenatal pesticide exposure may adversely affect child neurodevelopment, and this may partly arise from impairing the placenta's vital role in fetal development. In a cohort of pregnant farmworkers from Thailand (N=248), we examined the links between urinary metabolites of pyrethroid pesticides during pregnancy, placental gene expression networks derived from transcriptome sequencing, and newborn neurobehavior assessed using the NICU Network Neurobehavioral Scales (NNNS) at 5 weeks of age. The urinary concentrations of cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA) during pregnancy were found to be significantly positively correlated with the NNNS scores for attention (β = 0.49, p = 0.005), handling (β = 1.04, p = 0.04), and excitability (β = 0.15, p = 0.02). The urinary concentrations of trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (trans-DCCA) also showed a significant positive association with attention (β = 0.49, p = 0.01). Focusing on the 21 gene network modules in the placenta identified by Weighted Gene Co-expression Network Analysis (WGCNA), our analysis revealed significant associations between metabolites and nine distinct modules, and between thirteen modules and NNNS, with eight modules showing overlap. Notably, stress was negatively associated with the middleblue module (interferon alpha response) and the salmon module (Myc target). The middleblue module was correlated with attention, arousal, and quality of movement. The analysis also highlighted the first and third trimesters as critical periods for the influence of exposures on placental function, with pyrethroid metabolites measured early in pregnancy significantly negatively associated with the turquoise module (protein secretion), and those measured later in pregnancy having negative associations with modules related to Oxidative Phosphorylation (OXPHOS) and DNA repair. Additionally, the cumulative sum of 3PBA across pregnancy was significantly negatively associated with the lightyellow module (OXPHOS). These findings suggest that prenatal exposure to pyrethroid pesticides may influence neonatal neurobehavior through specific placental mechanisms that impact gene expression and metabolic pathway, and that the effects of environmental pyrethroid exposures on fetal neurodevelopment varies throughout pregnancy. These results offer valuable insights for future risk assessment and intervention strategies. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was Supported by the US National Institutes of Health (NIH) National Institute of Environmental Health Sciences (NIEHS) grants (R01ES029212, R01ES026082, and P30ES019776). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All study protocols were stringently reviewed and approved by the Institutional Review Boards of Emory University and the Ethical Review Board of the Institute of Health Sciences at Chiang Mai University. Informed consent was obtained from all participants prior to data collection, ensuring compliance with international ethical standards. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors