Prenatal exposure to the pesticides chlorpyrifos and 2,4-Dichlorophenoxyacetic acid is associated with circulating levels of reproductive hormones in healthy infant girls.

BACKGROUND

Pesticides are widespread in the environment and suspected endocrine disruptors that may interfere with sex hormones. Following the chlorpyrifos ban in 2020, use of alternative pesticides has increased; 2,4-Dichlorophenoxyacetic acid (2,4-D) remains widely used. This study examined the association between maternal pesticide exposure and pituitary, gonadal, and adrenal hormones in offspring during infancy.

METHODS

We recruited pregnant women from 2010 to 2012 in the Odense Child Cohort, including 489 mother-child pairs. Maternal urinary concentrations of the generic pyrethroid metabolite 3-phenoxybenzoic acid (3-PBA), the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCPY), and the herbicide 2,4-D were measured at gestational week 28. Serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), estrone (E1), estradiol (E2), 17-hydroxyprogesterone (17-OHP), Androstenedione (Adione), and Dehydroepiandrosterone sulfate (DHEAS) were assessed in infancy. Associations between prenatal pesticide exposure and offspring reproductive hormones (expressed as age- and sex-specific standard deviation (SD) scores) were assessed using multivariate linear regression.

RESULTS

In girls, higher maternal urinary TCPY and 2,4-D concentrations were associated with lower LH (-0.07 SD, 95 % CI: - 0.13; - 0.01 and - 0.06 SD, 95 % CI: - 0.11; - 0.02, per 1 µg/L increase, respectively); there were trends towards associations between 3-PBA, TCPY, 2,4-D and lower LH, FSH, E1 and E2, respectively. No associations were seen in boys.

CONCLUSION

In this low-exposed cohort, prenatal exposure to chlorpyrifos and 2,4-D may affect the reproductive hormones in girls, but not boys, during minipuberty, which may have long-term implications. This is of public health concern given the fact that > 90 % of participants were exposed.