November 15, 2012 — Couples with high levels of certain chemicals and pollutants in their blood took 20% longer to get pregnant than others with lower exposures, according to an NIH study published Wednesday in Environmental Health Perspectives, USA Today reports.
PCBs, or polychlorinated biphenyls, were used from 1929 to 1979 as coolants and lubricants (Szabo, USA Today, 11/14). Although PCBs now are banned in the U.S., there are still traces that can be found in the environment, such as in soil, water and the food chain.
Researchers at NIH and other institutions followed 501 couples from Michigan and Texas who were trying to conceive, testing them for exposure to 63 chemicals. In addition to blood samples, the couples were asked to keep daily records on sexual activity, menstrual cycles, and other factors like diet and exercise. The couples were followed until they became pregnant or for up to one year of trying. The study ran from 2005 to 2009.
Throughout the study, 347 couples became pregnant, while 154 couples did not become pregnant or dropped out of the study (Corbett Dooren, Wall Street Journal, 11/14). The study found that five chemicals affected women's fertility and 12 chemicals affected men's fertility. In addition to PCBs' effect on fertility, researchers also found that women with high levels of flame retardant had a 20% lower chance of conceiving and that men with high levels of DDT -- a pesticide that now is banned in the U.S. -- had a 17% lower rate of conception (USA Today, 11/14).
Germaine Buck Louis, the study's lead author, said that although many of the chemicals in the study are no longer produced, nearly everyone has measurable levels of the substances in their blood (Wall Street Journal, 11/14).
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Andrea Friedman, associate editor & director of reproductive health programs, National Partnership
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