In Utero Glyphosate Exposure and Anogenital Distance in Newborns from The Infant Development and Environment Study (TIDES)

Abstract

Background: Human exposure to glyphosate has become ubiquitous as its presence in the environment rises. Recent studies have described some endocrine disrupting effects of glyphosate. Specifically, in our work in rodents we observed an association between gestational exposure to low-dose glyphosate and Roundup® (a glyphosate-based herbicide) and longer anogenital distance (AGD), a marker of the prenatal hormone milieu, in male and female pups, suggesting an androgenic effect. In this pilot human study, we examined relation between in utero glyphosate exposure and newborn AGD. Methods: We measured glyphosate and its degradation product aminomethylphosphonic acid (AMPA) in 2nd trimester maternal urine from 100 pregnant women from the TIDES cohort (50 females and 50 males). Study staff obtained two measures of AGD; the anopenile and anoscrotal distances (males) and the anoclitoral and anofourchette distances (females). We used the median glyphosate and AMPA concentration to classify subjects into low and high exposure. The relation between exposure and AGD was evaluated using sex-stratified multivariable linear regression adjusted for age at exam, weight-for-length Z-scores, study center, gestational age, maternal age and urine collection time. Results: Glyphosate and AMPA concentrations were above the limits of detection in 95% and 93% of the samples, respectively. Glyphosate and AMPA urinary concentrations were highly correlated (r=0.57, P=7.6x10-10), with glyphosate levels (median, 0.23 ng/mL) higher than AMPA (median, 0.15 ng/mL). High (above median) glyphosate and AMPA were both statistically significantly (P<0.05) associated with increased AGD in females. In males, associations were also positive, but weaker and non-significant. Conclusion: These preliminary findings demonstrate measurable glyphosate exposure in the general population, and suggest a link between in utero glyphosate exposure and longer AGD particularly in females. Given the increasing glyphosate exposure in the US population and its potential role as an endocrine disruptor, this prevalent exposure warrants evaluation in larger studies.