Prenatal exposure to residential PM2.5 and anogenital distance in infants at birth: A birth cohort study from Shanghai, China.

Fine particulate matter (PM2.5) is believed to be one of the most hazardous air pollution with a ubiquitous presence. Animal studies have reported the association between prenatal exposure to traffic pollutant (not exclusively including PM2.5) and reproductive development in male offspring. However, the effects of prenatal exposure to PM2.5 on reproductive health in children are still unknown. The present study was based on the Shanghai-Minhang Birth Cohort Study (S-MBCS). A total of 876 pregnant women and their infants were included. Infants' anogenital distance (AGD, the distance from the anus to the genitals; AGDap [anus-penis] and AGDas [anus-scrotum] for boys, and AGDac [anus-clitoris] and AGDaf [anus-fourchette] for girls) were measured at birth. PM2.5 concentrations during pregnancy were estimated using satellite based modeling approach. Multiple linear regression analysis and multiple informant model were conducted to examine the associations between prenatal exposure to PM2.5 (pre μg/m3) and offspring's AGDs (mm). In order to minimize the misclassification of exposure, a sensitivity analysis restricted to mothers being off work during pregnancy was performed. In multiple linear regression models, we found that prenatal exposure to PM2.5 during the 1st and 3rd trimesters was associated with shorter AGDs. In multiple informant model, similar patterns were found, and statistically significant reductions were observed in AGDap (β=-0.278, 95%CI: -0.343∼-0.212), AGDac (β=-0.188, 95%CI: -0.247∼-0.130) and AGDaf (β= -0.163, 95%CI: -0.238∼-0.088) with PM2.5 exposure during the 1st trimester, and AGDap (β=-0.201, 95%CI: -0.247∼-0.155), AGDas (β=-0.158, 95%CI: -0.198∼-0.117), AGDac (β=-0.128, 95%CI: -0.167∼-0.089) and AGDaf (β = -0.144, 95%CI: -0.194∼-0.094) with PM2.5 exposure during the 3rd trimester. The sensitivity analysis restricted to women being off work during pregnancy showed similar results. PM2.5 exposure during the 1st and 3rd trimesters was associated with shortened AGDs in offspring at birth. Our findings provide preliminary evidence that prenatal exposure to PM2.5 might be associated with the reproductive development of offspring.