Evidence of Urine Glyphosate Exposure in Pregnant Women: A Prospective Midwest Birth Cohort

摘要

Glyphosate (GLY) is the most heavily used herbicide worldwide. GLY is a known endocrine-disruptors and suspected to affect birth outcomes. However, there are currently no published estimates of GLY exposure in US pregnant women to establish whether environmental levels of GLY are safe for fetuses. Therefore, we designed a prospective and cross-sectional birth cohort study to measure GLY exposure in pregnant women and evaluate its association with birth outcomes. Urine and drinking water samples were obtained from 71 pregnant women with singleton births in Midwestern US. The mean age of women was 29 (range 18-39) and 67 (94.4%) pregnancies were Caucasians. The pregnancy outcomes, questionnaires relating to food and water intake and other demographic, and maternal risk factors were also collected. Urine and water samples were measured for GLY using mass spectrometry (Agilent LC 1260 Triple Quadrupole MS). Linear models were used to assess relationships between GLY levels and determinants of fetal risk (Gestational length and birthweight). 93% pregnancies tested positive for GLY. Mean GLY was 3.39ng/mL (range 0.5-7.2ng/mL). The GLY levels were found negatively related to gestation length (r= -0.28, p=0.0202) and birth weight (r= -0.20, p=0.090) respectively. In addition, GLY levels were found higher in women who lived in rural areas (means of GLY 4.15 vs. 3.47, p=0.03). All drinking water samples tested negative for GLY. Our study provides first direct measure of GLY exposure in US pregnant women and its association with gestational length and birth weight. Since water samples tested negative, food ingestion is assumed to be the main route of exposure, however, the contribution of inhalation route needs to be evaluated. These preliminary evidences are concerning, and a detailed research is warranted to establish their association with adverse fetal growth and underlying toxicity mechanism for risk characterization.