Distribution and determinants of pesticide mixtures in cord serum using principal component analysis.

We characterized the distribution and determinants of fetal exposures to pesticide mixtures using a cross-sectional study of 297 singletons delivered at Johns Hopkins Hospital in Baltimore, MD (2004-2005). Concentrations of nine persistent and twelve nonpersistent pesticides were measured in cord serum. Mixtures were identified using principal components analysis. Associations between mixtures and maternal and infant characteristics were evaluated using multivariate analysis. p,p'-DDE, p,p'-DDT, trans-nonachlor, oxychlordane, bendiocarb, propoxur, and trans- and cis-permethrin were detected in 100, 90, 93, 84, 73, 55, 52, and 41% of serum samples, respectively. There were four independent pesticide components: DDT (p,p'-DDT + p,p'-DDE), chlordane (trans-nonachlor + oxychlordane), permethrin (trans- and cis-permethrins + PBUT), and carbamate (bendiocarb + propoxur). DDT and chlordane were 6.1 (95%CI: 2.4, 15.5) and 2.1 (95%CI: 1.0, 4.2) times higher for infants of women >35, and 1.8 (95%CI: 1.2, 2.9) and 1.5 (95%CI: 1.1, 2.1) times higher in smoking mothers. DDT and carbamate were 15 (95%CI: 7, 30) and 2 (95%CI: 1, 4) times higher for infants of Asian compared with Caucasian mothers. No significant differences were observed for permethrin. Fetal exposures to pesticides are widespread, occur as mixtures, and differ by maternal race, age, and smoking status.