Prenatal Neonicotinoid Insecticides Exposure, Oxidative Stress, and Birth Outcomes.

Background: An increasing number of studies have reported neonicotinoid insecticides (NEOs), the emerging alternatives to conventional insecticides, may increase oxidative stress and cause adverse health effects, but limited is known about the prenatal NEOs exposures and their impact on birth outcomes. Objectives: We investigated the levels of prenatal exposure to NEOs/metabolites, to assess their associations with birth outcomes, and investigate whether these associations could be mediated by oxidative stress using 8-OHdG as the biomarker. Methods: We studied 296 mother-infant pairs recruited from Laizhou Wan Birth Cohort in 2010 - 2013. Two NEOs (IMI and ACE), three metabolites (6-CN, ND-ACE, and 2CTCA), and 8-OHdG were measured in maternal urine collected before delivery. Birth outcomes including birth weight, birth length, ponderal index (PI), head circumference, and gestational age, were acquired. We examined the associations between NEOs/metabolites and birth outcomes using multivariable linear regression. Mediation analysis was conducted to clarify the role of 8-OHdG on the association of NEOs/metabolites exposure and birth outcomes. Results: Highest detection rate was observed for ACE (100.0%), followed by IMI (98.3%) and 6-CN (98.0%), suggesting the common exposure of pregnant women. The highest median concentration was observed for 6-CN with creatinine-adjusted median levels of 9.58 mu g/g creatinine. A decrease in newborns' head circumference was observed with a 10-fold increase in IMI (beta = -1.83; 95% CI = -3.04,-0.62) and ACE (beta =-2.27; 95% CI = -3.56,-0.98). An increase in newborns' PI was observed with a 10-fold increase in IMI (beta = 0.40; 95% CI = 0.03, 0.75). Maternal 8-OHdG demonstrated 38.5-65.5% mediating effects in the negative association of IMI, ACE, 2-CTCA with head circumference. These associations might differ between boys and girls. Conclusions: Pregnant women were widely exposed to NEOs/metabolites in China. Results suggested the potential impacts of prenatal exposure to certain neonicotinoid insecticides on head circumference. Urinary 8-OHdG may partly mediate these associations.