Pesticide exposure, birth size, and gestational age in the ISA birth cohort, Costa Rica.

PURPOSE: To examine associations of prenatal biomarkers of pesticide exposure with birth size measures and length of gestation among newborns from the Infants Environmental Health (ISA) birth cohort, Costa Rica. METHODS: We included 386 singleton liveborn newborns with data on birth size measures, length of gestation, and maternal urinary biomarkers of chlorpyrifos, synthetic pyrethroids, mancozeb, pyrimethanil, and 2, 4-D during pregnancy. We associated biomarkers of exposure with birth outcomes using multivariate linear regression and generalized additive models. RESULTS: Concentrations were highest for ethylene thiourea (ETU, metabolite of mancozeb), median = 3.40; p10-90 = 1.90-6.79 µg/L, followed by 3,5,6-trichloro-2-pyridinol (TCP, metabolite of chlorpyrifos) p50 = 1.76 p10-90 = 0.97-4.36 µg/L, and lowest for 2,4-D (p50 = 0.33 p10-90 = 0.18-1.07 µg/L). Among term newborns (≥37 weeks), higher prenatal TCP was associated with lower birth weight and smaller head circumference (e.g., β per 10-fold-increase) during the second half of pregnancy = -129.6 (95% confidence interval [CI] = -255.8, -3.5) grams, and -0.61 (95% CI = -1.05, -0.17) centimeters, respectively. Also, among term newborns, prenatal 2,4-D was associated with lower birth weight (β per 10-fold-increase = -125.1; 95% CI = -228.8, -21.5), smaller head circumference (β = -0.41; 95% CI = -0.78, -0.03), and, during the second half of pregnancy, with shorter body length (β = -0.58; 95% CI = -1.09, -0.07). Furthermore, ETU was nonlinearly associated with head circumference during the second half of pregnancy. Biomarkers of pyrethroids and pyrimethanil were not associated with birth size, and none of the biomarkers explained the length of gestation. CONCLUSIONS: Prenatal exposure to chlorpyrifos and 2,4-D, and, possibly, mancozeb/ETU, may impair fetal growth.