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Food, Agriculture, Pollution, Public Health

Prenatal exposure to pesticides linked to gestational age and birthweight

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Despite increasing awareness of the potentially harmful effects of pesticides — volatile organic compounds, parabens and DEHP — on human health, these chemicals can still be found in consumer goods. Another example are organophosphates (OP), which are often used in insecticides, flea collars and pet shampoos. Severe OP poisoning can result in seizures and death; even limited exposure has been linked to significant developmental delays in children.

A 2012 study published in Environmental Health Perspectives, “Associations of Prenatal Exposure to Organophosphate Pesticide Metabolites with Gestational Age and Birthweight,” used data from 344 mother/child pairings in Cincinnati to measure the relationship between a child’s levels of prenatal OP pesticide exposure and her gestational age and birthweight. Study participants were adult women with household incomes between $55,000 and $85,000; the majority of participants were white (62%), married (68%) and between the ages of 25 and 35 (60%). The study was a joint effort by researchers at Emory University, Harvard University, Simon Fraser University, the Centers for Disease Control and Prevention, BC Children’s Hospital in Vancouver and Cincinnati Children’s Hospital Medical Center.

Key study findings include:

  • “Prenatal urinary DAP [Dialkyl Phosphate] concentrations were associated with shortened gestation and reduced birthweight in this cohort, but the effects differed by race/ethnicity and … genotypes.”
  • A 10-fold increase in OP pesticide concentrations in the mother was associated with a 0.5 week decrease in the infant’s gestational age. The same increase in maternal prenatal OP pesticide exposure is associated with a decline in birthweight of 151 grams (adjusted to account for changes in gestational age): “We found that maternal exposure to OP insecticides … was inversely associated with gestational age and birthweight.”
  • The relationship between OP pesticide concentrations and gestational age was stronger for white newborns (-0.7 weeks) than for black newborns (-0.1 weeks). The authors note that “maternal race/ethnicity may also be acting as a proxy for a combination of conditions — socioeconomic factors, genetic susceptibility, psychological stressors, and environmental toxicants — only some of which were measured in our study.”
  • “Diet and home pesticide use have been identified as important routes of exposure in non-agricultural populations, although [an earlier study] found that switching children from conventional to organic diets for several days reduced urinary OP metabolites to levels near or below the limit of detection, suggesting that diet was the primary source of exposure in that study population.”

The study’s authors conclude that “although their use in the United States has declined in recent years, exposures to organophosphate insecticides remain widespread.”

Tags: children, consumer affairs, pollution, parenting

    Writer: | Last updated: May 2, 2012

    Citation: Rauch, SA; et al. "Associations of Prenatal Exposure to Organophosphate Pesticide Metabolites with Gestational Age and Birth Weight," Environmental Health Perspectives, July 2012, Vol. 120, No. 7, 1055-1060. doi: 10.1289/ehp.1104615.

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    Media analysis

    Read the issue-related CBC News article titled "Common Pesticides Linked to Lower Birth Weights."

    1. What key insights from the study and article should reporters be aware of as they cover issues relating to pesticide exposure and public health?

    Study analysis

    Read the full study titled "Associations of Prenatal Exposure to Organophosphate Pesticide Metabolites with Gestational Age and Birthweight."

    1. What are the study's key technical term(s)? Which ones need to be put into language a lay audience can understand?
    2. Do the study’s authors put the research into context and show how they are advancing the state of knowledge about the subject? If so, what did the previous research indicate?
    3. What is the study’s research method? If there are statistical results, how did the scholars arrive at them?
    4. Evaluate the study's limitations. (For example, are there weaknesses in the study's data or research design?)
    5. How could the findings be misreported or misinterpreted by a reporter? In other words, what are the difficulties in conveying the data accurately? Give an example of a faulty headline or story lead.

    Newswriting and digital reporting assignments

    1. Write a lead, headline or nut graph based on the study.
    2. Spend 60 minutes exploring the issue by accessing sources of information other than the study. Write a lead (or headline or nut graph) based on the study but informed by the new information. Does the new information significantly change what one would write based on the study alone?
    3. Compose two Twitter messages of 140 characters or fewer accurately conveying the study’s findings to a general audience. Make sure to use appropriate hashtags.
    4. Choose several key quotations from the study and show how they would be set up and used in a brief blog post.
    5. Map out the structure for a 60-second video segment about the study. What combination of study findings and visual aids could be used?
    6. Find pictures and graphics that might run with a story about the study. If appropriate, also find two related videos to embed in an online posting. Be sure to evaluate the credibility and appropriateness of any materials you would aggregate and re-purpose.

    Class discussion questions

    1. What is the study’s most important finding?
    2. Would members of the public intuitively understand the study’s findings? If not, what would be the most effective way to relate them?
    3. What kinds of knowledgeable sources you would interview to report the study in context?
    4. How could the study be “localized” and shown to have community implications?
    5. How might the study be explained through the stories of representative individuals? What kinds of people might a reporter feature to make such a story about the study come alive?
    6. What sorts of stories might be generated out of secondary information or ideas discussed in the study?