Goodman, M., Mandel, J. S., DeSesso, J. M., & Scialli, A. R. (2014). Atrazine and pregnancy outcomes: a systematic review of epidemiologic evidence. Birth defects research. Part B, Developmental and reproductive toxicology. https://doi.org/10.1002/bdrb.21101
Goodman M, Mandel JS, DeSesso JM, Scialli AR. Atrazine and pregnancy outcomes: a systematic review of epidemiologic evidence. Birth defects research. Part B, Developmental and reproductive toxicology. 2014. doi:10.1002/bdrb.21101
Goodman, M., et al. "Atrazine and pregnancy outcomes: a systematic review of epidemiologic evidence." Birth defects research. Part B, Developmental and reproductive toxicology, 2014.
Human studies find no consistent atrazine link to pregnancy outcomes
No outcome category showed a consistent positive association with atrazine exposure across studies, a 2014 systematic review of human studies found. The studies examined birth defects, miscarriage, small newborn size and preterm birth. Most used aggregate data for exposure, or for both exposure and outcome. The authors rate the quality of the data as poor.
Key Findings
None of the outcome categories, including birth defects, small for gestational age birth weight and preterm delivery, showed consistent positive associations with atrazine across studies from 1992 through May 2013.
Most positive birth defect results (7 of 10) came from Tier 3 studies using aggregate data for exposure and outcome. Most Tier 1 studies, using individual-level data, were consistent with no association.
Preterm delivery was associated with high county water exposure in Kentucky (odds ratios 1.2 to 1.26) and paternal yard exposure in Canada (odds ratio 4.9, 95% CI 1.6 to 15.0).
Living in atrazine-use areas was associated with gastroschisis in two studies and, among older mothers, in a third; two others found none. The authors call exposure data in all inadequate.
Only one study, a French cohort sample of 579, measured atrazine metabolites in urine. Its odds ratio for major malformations with direct exposure was 1.0 (95% CI 0.3 to 3.1).
Interpretation
The paper is a systematic review of epidemiologic studies, which compare outcomes in people with higher and lower exposure. Results could not be pooled because methods and reporting varied, so the authors labeled each study positive, null or mixed. The studies came from the United States, Canada, France and Poland. The authors conclude that claims of a causal link between atrazine and adverse pregnancy outcomes are not warranted. They report an unrestricted grant from Syngenta Crop Protection and state the company had no role in the design, analysis or manuscript.
RRM Context
Restorative reproductive medicine takes a root-cause view of reproductive health. Environmental exposures belong in that picture for both partners. Several studies in this review recorded fathers' exposure as well as mothers'. The authors call for studies that measure each person's exposure and see promise in urine tests.
Our editorial summary of this paper, not the article's abstract.
Abstract
Atrazine (ATR) is a commonly used agricultural herbicide that has been the subject of epidemiologic studies assessing its relation to reproductive health problems. This review evaluates both the consistency and the quality of epidemiologic evidence testing the hypothesis that ATR exposure, at usually encountered levels, is a risk factor for birth defects, small for gestational age birth weight, prematurity, miscarriages, and problems of fetal growth and development. We followed the current methodological guidelines for systematic reviews by using two independent researchers to identify, retrieve, and evaluate the relevant epidemiologic literature on the relation of ATR to various adverse outcomes of birth and pregnancy. Each eligible paper was summarized with respect to its methods and results with particular attention to study design and exposure assessment, which have been cited as the main areas of weakness in ATR research. As a quantitative meta-analysis was not feasible, the study results were categorized qualitatively as positive, null, or mixed. The literature on ATR and pregnancy-related health outcomes is growing rapidly, but the quality of the data is poor with most papers using aggregate rather than individual-level information. Without good quality data, the results are difficult to assess; however, it is worth noting that none of the outcome categories demonstrated consistent positive associations across studies. Considering the poor quality of the data and the lack of robust findings across studies, conclusions about a causal link between ATR and adverse pregnancy outcomes are not warranted.
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