THURSDAY, Jan. 29, 2009 (HealthDay News) -- Chemicals known as perfluorinated chemicals, which are pervasive in food packaging, pesticides, clothing, upholstery, carpets and personal care products, may delay pregnancy, a new study suggests.
These chemicals are being phased out in the United States because of their toxic effects, and are expected to be completely gone by 2010. However, they remain in the environment and in the body for decades, and have been linked to developmental problems.
"These widespread chemicals apparently lower the fertility in couples trying to get pregnant," said lead researcher Dr. Jorn Olsen, chairman of the Department of Epidemiology at UCLA's School of Public Health.
Danish women in the study who had with high levels of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) took longer to get pregnant, Olsen said.
"If this finding can be replicated, one would have to look for other chemicals to replace these," he said.
The report is published in the Jan. 29 online edition of Human Reproduction. And it follows on the heels of a report linking another common plastic chemical, bisphenol A (BPA), to developmental problems in fetuses and infants.
For the study, Olsen's team collected data on 1,240 women who participated in the Danish National Birth Cohort. The researchers took blood samples from the women and interviewed them on how long it took them to become pregnant.
The researchers found that blood levels of PFOS ranged from 6.4 nanograms per milliliter (ng/ml) to 106.7 ng/ml. For PFOA, levels ranged from 1 ng/ml to 41.5 ng/ml.
Olsen's group then divided the women into four groups, depending on how much of the chemicals was in their blood.
Women in the three groups with the highest levels of PFOS took from 70 percent to 134 percent longer to get pregnant than women with the lowest PFOS levels, the team report. It took women with the highest PFOA levels 60 percent to 154 percent longer to get pregnant compared with women with the lowest levels of this chemical.
Why these chemicals would delay pregnancy isn't known, Olsen said, but they may affect hormones involved in reproduction.
Recent animal studies have found these chemicals may have a variety of toxic effects on the liver, immune system and developmental and reproductive organs, he noted.
In addition, previous studies by the same researchers found that PFOA may affect the growth of fetuses. In addition, two other studies linked PFOA and PFOS to impaired fetal growth, Olsen said.
However, Dr. Jamie Grifo, director of reproductive endocrinology at New York University Medical Center in New York City, believes the study is missing a cause-and-effect relationship.
"There are probably things in the environment that are affecting us in ways we don't know about, but you have to get to the basic biology of what's the mechanism of action -- that's the missing link," Grifo said. "The problem with the study is, it creates more anxiety and fear, but it doesn't answer the question."
Any danger with these chemicals may soon become moot, since in 2006 the U.S. Environmental Protection Agency (EPA) had commitments from eight manufacturers of PFOA to voluntarily reduce emissions and product content of PFOA and related chemicals in the United States and overseas by 95 percent by 2010, and to work toward eliminating emissions and product content of these chemicals by 2015. This action was brought on because the chemical was associated with "systemic and developmental toxicity."
In addition, 3M, the only manufacturer of PFOS in the United States, had agreed to phase out its production and use of the chemical nine years ago, according to the EPA's Web site.
For more information on infertility, visit the U.S. National Library of Medicine .