Maternal organophosphate pesticide exposure in relation to birthweight: Modification by placenta transporter genotype.

Exposure to organophosphate pesticides (OPPs) has been linked to adverse birth outcomes, including low birthweight. Maternal biomarkers are commonly used as proxies for fetal exposure, but fetal exposure also depends on placental transport mechanisms. In 240 mother-newborn pairs, we explored how genetic variation in membrane transporters influences the association between maternal OPP concentrations and birthweight. Single nucleotide polymorphisms (SNPs) in the OAT4/SLC22A11 and OATP2B1/SLCO2B1 membrane transporters modified the relationship between OPP exposure and birthweight-for-gestational age, with significant inverse associations observed only among individuals with variant transporter genotypes. In this small study, we found that transporter genotype may influence the placental disposition of environmental chemicals and perinatal susceptibility to toxicity.