Research Shows Low-Dose Exposures to Active Ingredients of Agricultural and Lawn Care Pesticides May Harm Developing Embryos

Women Trying to Conceive Advised to Carefully Follow Product Label


May 17, 2004, 01:00 ET from Marshfield Clinic

    MARSHFIELD, Wis., May 17 /PRNewswire/ -- Low-dose exposures to
 agricultural and lawn care pesticides may cause injury to developing embryos
 before a pregnancy is even noticed, according to a study conducted by
 researchers at Marshfield Clinic Research Foundation (MCRF), Marshfield, Wis.,
 and being published in the May 2004 issue of Environmental Health
 Perspectives, the journal of the National Institute of Environmental Health
 Sciences, National Institutes of Health.
     "In research conducted with mouse embryos, injury was observed during
 laboratory studies with a variety of agrochemicals and lawn care products,
 such as weed and insect killers and fertilizers, at concentrations previously
 assumed to be without adverse health consequences for humans," said Anne
 Greenlee, Ph.D., lead author of the article.
     Types of injury observed included slowed embryonic development and
 reductions in the number of cells comprising the embryo, both of which may
 contribute to implantation failures and lengthening in time needed to achieve
     Since it is impossible to define precisely the amount of chemical(s)
 dangerous to an individual's reproductive health, a cautious approach seems
 best, Greenlee said.
     "Women considering or trying to conceive should make every effort to
 minimize their exposure to lawn care and agrochemical products," Greenlee
 said. "Applying these products according to label guidelines and wearing
 protective gear, such as masks or gloves, can help reduce exposure. It's also
 important to adhere to the length of time manufacturers recommend you remain
 off your lawn or field after using pesticides, herbicides and fertilizers."
     Greenlee, a scientist in Marshfield Clinic Research Foundation's National
 Farm Medicine Center (NFMC), said her lab conducted the study because little
 is known about residential use of pesticides and their possible effects on
 embryonic development in the first few days of pregnancy. Her study used mouse
 embryos to model possible human effects as embryos of different animal species
 react similarly at this early stage of development.
     Greenlee stressed the importance of additional work needed to validate
 these findings for purposes of human risk assessment and to determine
 relevance of lab results to pregnancy outcomes.
     In this study, researchers examined 13 agrochemicals and lawn care
 herbicides (weed killers) for their effects on embryo development during the
 preimplantation period. The preimplantation period corresponds to the first to
 seventh day of pregnancy, when an embryo is rapidly dividing and before
 implantation occurs in the mother.
     The study, funded by the Wisconsin Department of Agriculture, Trade and
 Consumer Protection (DATCP) and MCRF disease-specific research funds, examined
 active ingredients in commercial pesticide formulations. Agricultural
 chemicals studied are typical of those used in the upper Midwest. Lawn
 pesticides studied are typical of those used throughout the United States.
     Active ingredients tested included six herbicides (atrazine, dicamba,
 metolachlor, 2,4-D, pendimethalin, MCPP); three insecticides (chlorpyrifos,
 terbufos, permethrin); two fungicides (chlorothalonil, mancozeb); one drying
 agent (diquat) and one fertilizer (ammonium nitrate).
     Greenlee's manuscript, "Low-dose Agrochemicals and Lawn Care Pesticides
 Induce Developmental Toxicity in Murine Preimplantation Embryos," is published
 online at . Additional
 authors are Tammy Ellis, NFMC; and MCRF Biostatistician Dick Berg, M.S.
     Research published by Greenlee in the July 2003 issue of the journal
 Epidemiology showed that women who mix and apply pesticides or apply
 fungicides in the two-year period before trying to conceive significantly
 increase their chances of infertility.  In that study, it was shown that
 infertile women were 27 times more likely to have mixed and applied pesticides
 than women who had become pregnant.
     The Marshfield Clinic system consists of 40 patient care and research and
 education facilities in Northern, Central, Eastern and Western Wisconsin,
 making it one of the largest comprehensive medical systems in the United
     Editor's Note:
      -- The general term "pesticides" refers to herbicides (weed killers),
         insecticides (insect killers), fungicides (fungus/mold killers) and
      -- Within hours of online publication, the Environmental Protection
         Agency (EPA) asked to review Greenlee's data and publication for
         possible inclusion in the re-registration decision process for 2,4-D,
         one of the chemicals analyzed in her study.
         Re-registration is required for pesticides initially registered before
         November 1984. These pesticides must undergo a complete review as part
         of compliance with the Food Quality Protection Act (FQPA). The
         Re-Registration Eligibility Decision (RED) will summarize the risk of
         the product as well as what can be done to reduce the risk to
         applicators, workers, and consumers if the pesticide continues to be
         used in the United States. Many commonly used pesticides fall into
         this group.
      -- Previous studies have suggested that exposure to high doses of
         pesticides, such as those experienced by pesticide applicators
         (professionals who apply pesticide to lawns, gardens and farmland),
         may be associated with adverse reproductive outcomes, including
         spontaneous abortion, birth defects and parental risk of infertility.

SOURCE Marshfield Clinic