Bystander Agricultural Pesticides Exposure and the Risk of Adverse Reproductive Outcomes: A Review of the Literature

Abstract

Background and Objectives: Over the last decade, there has been growing concern about the possible health effects including a number of adverse reproductive outcomes from pesticides exposure for people living near agricultural field—so called “bystander exposure”. This systematic review evaluates the current epidemiological evidence on the association between bystander pesticide exposure and birth outcomes including congenital malformations, still birth, intrauterine growth retardation, low birth weight, preterm birth and spontaneous abortions. Methods: We identified and reviewed twenty five bystander exposure studies using a systematic search of the main scientific databases and other approaches for the period of 1950 to 2007. Study methodologies and main results were summarized and tabulated according to the year of study and type of adverse reproductive outcome studied. The studies described and then evaluated for their level of evidence for reproductively toxicity in humans. Results: Overall, there is some evidence for a relationship between bystander pesticide exposures and adverse birth outcomes, but the strength of the evidence varies between outcomes. The evidence is suggestive of an association between bystander pesticide exposure and congenital malformations, but due to some limitations, such as weaknesses in the exposure assessment and the possibility of chance or confounding bias, further studies are needed. For the other birth outcomes (still birth, IUGR, low birth weight, preterm birth and spontaneous abortion), the evidence as yet are inadequate to infer association, but the available evidence justifies further studies. Conclusion: There is some evidence for a relationship between bystander pesticide exposures and adverse birth outcomes, but further study is needed using improved exposure assessment methodologies to assess the risk, if any.