Perfluourinated chemicals (PFC) such as perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), man-made ubiquitous compounds, are commonly used in everyday items like food packaging, upholstery, pesticides, carpets, clothing, and personal care products. A novel study in evaluating the association between plasma PFC levels and pregnancy has demonstrated that exposure to PFCs may decrease fecundity in women. The findings of the research have been published in the recent issue of the journal Human Reproduction.

Chunyuan Fei from the University of California, Los Angeles, and colleagues, conducted the study on 1,240 women from the Danish National Birth Cohort recruited between 1996 and 2002 to analyze the effects of PFCs on the fertility in women. The investigators collected data on the time to pregnancy (TTP) and also if it was a planned or unplanned conception. Based on the time required to conceive, the subjects were divided into 5 categories (<1, 1–2, 3–5, 6–12 and >12 months). Either a TTP of >12 months or requirement of infertility treatment for the establishment of pregnancy was defined as infertility. At 4-14 weeks of pregnancy, plasma levels of PFOS and PFOA were measured. The PFOS levels varied between 6.4 to 106.7 ng/mL, while PFOA levels ranged between <1 to 41.5 ng/mL; and depending on the women’s PFC levels, 4 quartiles were formed.

Results demonstrated a link between longer TTP and higher maternal levels of PFOS and PFOA. The women in the higher three quartiles of PFOS and PFOA showed a respective 70-134% and 60-154% increase in the adjusted odds of infertility, compared to those in the lowest exposure quartile. On using Cox discrete-time models to estimate fecundity odds ratios (FORs), the study found that the adjusted FORs were almost similar for women in the lowest quartile and in three highest exposure groups of PFOS. However, a linear-like trend was noticed in the three highest PFOA exposure groups and women in the lowest quartile. Considering the findings, the scientists concluded that fertility is reduced in women exposed to PFOS and PFOA, especially in developed countries.

Earlier, a risk assessment report by the U.S. Environmental Protection Agency (EPA) suggested that PFOA, a component of Teflon production, is a risk factor for developmental and reproductive disorders. Following toxicological and bioaccumulation discoveries in the entire group of PFCs (especially PFOS), EPA withdrew PFOS, an active ingredient of 3M’s Scotchgard™ products, from the market in 2000. As the chemical properties of PFOA are similar to PFOS, EPA further analyzed PFOA and found that both the PFCs cause different types of cancers apart from several adverse effects. Based on the findings of several studies, it was demonstrated that PFOA caused infertility and increased birth defects in mothers exposed to the chemical, especially in PFOA-exposed plant workers.

According to EPA estimations, around 90% of the US population have PFOA in their blood, with few having levels as high as those found in factory workers. The July 2005 biannual National Report on Human Exposure to Environmental Chemicals by the US Centers for Disease Control and Prevention (CDC) indicated that more than 90% of the Americans have pesticides in their systems following the chemical revolution.

The National Center for Health Statistics (NCHS) reported that 7.3 million American women between 15 to 44 years had impaired fecundity in 2002. The current study, which suggests that PFC exposure reduces fertility in women, could further increase the socioeconomic and psychological burden associated with infertility. With many studies reporting the deleterious effects of some chemicals such as PFCs on human health, more stringent guidelines are required to test them before regulatory approval, thereby averting future health problems.

References

1. Fei C, McLaughlin JK, Lipworth L, Olsen J. Maternal levels of perfluorinated chemicals and subfecundity. Hum Reprod. 2009 Jan 28. [Epub ahead of print]

2. Warning: Teflon Can Cause Birth Defects & Infertility. Press Release. The National Health Federation. Last Accessed January 31, 2009.