Prenatal exposure to persistent organic compounds and their association with anogenital distance in infants

Research question What is the association between prenatal exposure to persistent organic pollutants, separately and combined, and anogenital distance (in-utero endocrine disruption marker). Design A cohort study conducted in Sonora, Mexico. Blood concentrations of polychlorobiphenyls (PCB) 28, 74, 118, 138/158, 153, 170, 180 and the isomers of dichlorodiphenyltrichloroethane (DDT) and its metabolites were determined in women in the third trimester of pregnancy; three variants of anogenital distance were measured on five occasions during the first year of life of their infants: 82 girls (402 observations) and 74 boys (356 observations). Results Boys had negative and significant associations between anogenital distance/height and the concentrations of PCB 28 (beta = − 0.005;P = 0.006), PCB 74 (beta = − 0.003;P = 0.013), and PCB 170 (beta = − 0.005;P = 0.001) when analysed individually. Negative and significant associations were also found using statistical models applied to mixtures of compounds. The latter associations were sometimes larger in magnitude and significance, suggesting a possible potentiation of the compounds. No associations were observed between anogenital distance and DDT in either sex or with PCB in girls. Conclusions The decreased anogenital distance associated with prenatal exposure to the persistent organic pollutants, observed consistently in different analyses, suggests an under-masculinizing effect of these environmental pollutants in boys.