Pyrethroid use has increased worldwide, resulting in extensive human exposure.
We examined in utero 3-PBA levels in relation to BSID-IIS scores at 2 and 3 years.
Participants with 3-PBA≥LOD had lower MDI scores at 2 years compared to those <LOD.
In utero 3-PBA levels were not associated with PDI scores at 2 or 3 years.
Additional study of in utero pyrethroid exposure and neurodevelopment is needed.