Liz Szabo, USA TODAY
A new study suggests that couples who have high levels of PCBs may take longer to conceive.
12:04AM EST November 14. 2012 – Although industrial chemicals called PCBs have been banned for more than three decades, a new study suggests that the pollutants could be making it harder for some people to have a baby today.
Couples with high levels of certain chemicals in their bodies took about 20% longer to conceive compared with those with lower exposures, says the study from the National Institutes of Health.
That type of delay is similar to the effects of other factors known to reduce fertility, such as smoking, obesity and older age, according to the findings, published today in Environmental Health Perspectives.
PCBs, or polychlorinated biphenyls, were widely manufactured from 1929 to 1979, with hundreds of uses, such as coolants and lubricants in electrical equipment, according to the Environmental Protection Agency.
Although they’re no longer manufactured, PCBs still may be present in older products, such as caulking, oil-based paint, floor finish and insulation. PCBs persist for years in the environment — in soil, water and the food chain — as well as in body fat, the EPA says. PCBs also are found in breast milk.
Studies have shown that PCBs and other chemicals, such as the banned pesticide DDT, can alter the hormone system, according to the Natural Resources Defense Council, an environmental group.
People can reduce their future exposure to PCBs by limiting their consumption of animal products, especially fatty meat, says study author Germain Buck Louis, a researcher at NIH, which funded the study. Yet because these and other chemicals are stored in fat, it’s not possible to completely eliminate the pollutants, says Shanna Swan, a professor at the Mount Sinai School of Medicine in New York.
Swan called the $10 million project “an amazing study” and “unprecedented in its cost, scope and details.” Researchers tried to contact more than 424,000 households, in order to find 500 couples who were going to try to conceive a baby within the next two months.
The study followed the couples for a year, and followed women through the end of any pregnancies. Only 0.1% of couples contacted were planning to try to conceive in that time, Louis says. Scientists asked couples to provide blood and urine samples before conceiving, as well as keep daily diaries, undergo frequent interviews and pregnancy tests.
Researchers measured levels of 63 environmental chemicals. Virtually everyone had detectable levels of PCBs and a breakdown product of the banned pesticide DDT, Louis says. The couple’s chances of conceiving each month then were calculated and showed that the likelihood of a pregnancy fell by about 20% among men and women with high exposure to certain types of PCBs…