Glyphosate and adverse pregnancy outcomes, a systematic review of observational studies.
A study in frog and chicken embryos, and reports of a high incidence of birth defects in regions of intensive GM-soy planting have raised concerns on the teratogenic potential of glyphosate-based herbicides. These public concerns prompted us to conduct a systematic review of the epidemiological studies testing hypotheses of associations between glyphosate exposure and adverse pregnancy outcomes including birth defects.



A systematic and comprehensive literature search was performed in MEDLINE, TOXLINE, Bireme-BVS and SCOPUS databases using different combinations of exposure and outcome terms. A case-control study on the association between pesticides and congenital malformations in areas of extensive GM soy crops in South America, and reports on the occurrence of birth defects in these regions were reviewed as well.



The search found ten studies testing associations between glyphosate and birth defects, abortions, pre-term deliveries, small for gestational date births, childhood diseases or altered sex ratios. Two additional studies examined changes of time-to-pregnancy in glyphosate-exposed populations. Except for an excess of Attention Deficit Hyperactivity Disorder - ADHD (OR = 3.6, 1.3-9.6) among children born to glyphosate appliers, no significant associations between this herbicide and adverse pregnancy outcomes were described. Evidence that in South American regions of intensive GM-soy planting incidence of birth defects is high remains elusive.



Current epidemiological evidence, albeit limited to a few studies using non-quantitative and indirect estimates and dichotomous analysis of exposures, does not lend support to public concerns that glyphosate-based pesticides might pose developmental risks to the unborn child. Nonetheless, owing to methodological limitations of existing analytical observational studies, and particularly to a lack of a direct measurement (urine and/or blood levels), or an indirect estimation of exposure that has proven valid, these negative findings cannot be taken as definitive evidence that GLY, at current levels of occupational and environmental exposures, brings no risk for human development and reproduction.
National Institute for Health Quality Control, Oswaldo Cruz Foundation - FIOCRUZ, Av. Brasil 4365, Rio de Janeiro, RJ, 21040-900, Brazil.
Jessica S A
JS
de Araujo
National Institute for Health Quality Control, Oswaldo Cruz Foundation - FIOCRUZ, Av. Brasil 4365, Rio de Janeiro, RJ, 21040-900, Brazil.
Isabella F
IF
Delgado
National School of Public Health, Oswaldo Cruz Foundation - FIOCRUZ, Av. Brasil 4036, EXCAM building, rooms 101-104, 913, Rio de Janeiro, RJ, 21040-361, Brazil. paum@ensp.fiocruz.br.
Francisco J R
FJ
Paumgartten
D000022:Abortion, Spontaneous / Q000139:chemically induced / Q000453:epidemiology*; D000383:Agriculture; D016022:Case-Control Studies; D000013:Congenital Abnormalities / Q000453:epidemiology / Q000209:etiology; D004781:Environmental Exposure / Q000009:adverse effects; D016021:Epidemiologic Studies; D005260:Female; D005998:Glycine / Q000031:analogs & derivatives* / Q000633:toxicity; D006540:Herbicides / Q000633:toxicity*; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D013020:South America / Q000453:epidemiology; D000097797:Glyphosate
D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate
Abortion; Agricultural workers; Attention deficit hyperactivity disorder; Birth defects; Congenital anomalies; Fecundity; Occupational exposure; Pesticides; Reproductive toxicity; Teratogenicity