The study by the UCSF research team marks the first time that the number of chemicals to which U.S. pregnant women are exposed has been counted.
The researchers analyzed data for 268 pregnant women from the National Health and Nutritional Examination Survey (NHANES) 2003-2004, a nationally representative sample of the U.S. population. Their findings are published in the journal "Environmental Health Perspectives," a publication of the federal government.
"It was surprising and concerning to find so many chemicals in pregnant women without fully knowing the implications for pregnancy," said lead author Tracey Woodruff, PhD, MPH, director of the UCSF Program on Reproductive Health and the Environment.
"Several of these chemicals in pregnant women were at the same concentrations that have been associated with negative effects in children from other studies. In addition, exposure to multiple chemicals that can increase the risk of the same adverse health outcome can have a greater impact than exposure to just one chemical," said Woodruff, an associate professor in the UCSF Department of Obstetrics and Gynecology and Reproductive Sciences.
Pregnant woman, New York, August 2010 (Photo by J.K. Braun)
Analyzing data for 163 chemicals, Woodruff and her team detected polychlorinated biphenyls, PCBs; organochlorine pesticides; perfluorinated compounds, PFCs; phenols; polybrominated diphenyl ethers, PBDEs; phthalates; polycyclic aromatic hydrocarbons, PAHs; and perchlorate in 99 to 100 percent of pregnant women.
Among the chemicals found in the study group were PBDEs, compounds used as flame retardants now banned in many states including California, and dichlorodiphenyltrichloroethane, DDT, an organochlorine pesticide banned in the United States in 1972.
Bisphenol A, which makes plastic hard and clear, and is found in epoxy resins that are used to line the inside of metal food and beverage cans, was identified in 96 percent of the women surveyed. Prenatal exposure to BPA has been linked to adverse health outcomes, affecting brain development and increasing susceptibility to cancer later in life, said the researchers.
"Our findings indicate several courses of action. First, additional research is needed to identify dominant sources of exposure to chemicals and how they influence our health, especially in reproduction," said Woodruff. "Second, while individuals can take actions in their everyday lives to protect themselves from toxins, significant, long-lasting change only will result from a systemic approach that includes proactive government policies."
"These findings should be a call to action for Congress and the administration." said Andy Igrejas, director of the nonprofit Safer Chemicals, Healthy Families coalition.
"We've known for years that exposures in the womb to toxic chemicals have a profound effect on the health of children," said Igrejas. "Here we have confirmation that pregnant women are carrying these chemicals around in their bodies."
Recent polling by Mark Mellman, of the Mellman Group, a Washington, DC-based polling and consulting firm, "has shown surprisingly strong bipartisan support for cracking down on toxic chemicals across demographic and regional lines," Igrejas said. Eighteen states have taken action on chemicals since 2002, passing 71 different laws with overwhelming bipartisan support. In the last Congress, however, legislation by Senator Frank Lautenberg, a New Jersey Democrat, and Congressman Henry Waxman, a California Democrat, was introduced but never brought up for a vote.
"Federal chemical policy reform is the best approach for tackling this major issue," said Igrejas. "At the voter level there is almost no daylight between Republicans and Democrats on this issue. Can Congress follow their lead? We're optimistic that they can."
Funding for the UCSF study was provided by the Pew Charitable Trusts and a grant from the Passport Science Innovation Fund.
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