Infertility linked to lawn chemicals by Marshfield Clinic researcher

Marshfield, Wis. – 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, 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, 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 pregnancy.

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, 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.

Researchers examined 13 agrochemicals and lawn-care herbicides 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 and Marshfield Clinic’s 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.