Flame retardants linked to longer time to get pregnant, finds California study.

Harley KG, AR Marks, J Chevrier, A Bradman, A Sjödin and B Eskenazi. 2010. PBDE concentrations in women's serum and fecundability. Environmental Health Perspectives http://dx.doi.org/10.1289/ehp.0901450.

Chemicals widely used to prevent fires in household products like furniture and electronics may contribute to fertility problems by lengthening the time it takes for a woman to get pregnant, according to study of low-income, mostly Mexican-American women living in California.

The study is one of the first to examine if PBDEs can affect human fertility.

Animal studies show that PBDEs can alter behavior, delay the onset of puberty and impact sex hormones and thyroid hormones. These, in turn, may influence ovulation, menstrual cycle regularity and fertility.

PBDEs are a class of chemicals used mainly as flame retardants in many industrial and consumer products. They are added to carpeting, furniture, textiles, foam products, electronics and plastics. Several types have been banned from use during the past decade, but exposure continues from furniture and other products that are still being used.

Since the chemicals can migrate out of the products, they are now found throughout the environment, including in soil, food, breast milk, and house dust.

Human exposure to PBDEs is almost universal, with higher levels found in the United States than in Europe. The chemicals are detected in the blood of 97 percent of American adults sampled. The highest levels are found in Californians, possibly because of the state's tough flammability standards.

Researchers interviewed 223 pregnant women enrolled in the Center for the Health Assessment of Mothers and Children of Salinas, an agricultural region of California. As part of the interview, women were asked how long it took them to get pregnant, whether or not they had regular menstrual periods before becoming pregnant and the length of their menstrual cycles. Personal information, reproductive histories and other exposures – smoking, alcohol, agricultural influences – were also gathered and taken into account during the statistical analysis. The women's blood was analyzed for four of the PBDE types most commonly measured in people.

The PBDEs were detected in 97 percent of the women. The higher the levels in the blood, the longer it took for the women to get pregnant. This association was true for each of the four chemicals and total PBDEs measured in the blood.

More specifically, the women were 30 percent less likely to become pregnant in a given month for every 10-fold increase in total blood PBDEs. PBDEs did not affect regularity or length of menstrual cycles.

This study focused on pregnant women, and therefore did not examine the role of PBDEs on male partners' fertility.