Published Jan. 26, 2010, in the journal Environmental Health Perspectives, the study measured levels of polybrominated diphenyl ethers (PBDEs) in blood samples from 223 pregnant women. (PBDEs are a type of flame retardant commonly found in household consumer products.) Women were also asked to recall how long it had taken to become pregnant.
After ruling out other fertility factors, researchers found that women with the highest concentrations of the chemicals experienced some of the longest wait times before conception. Each 10-fold increase in blood concentration of PBDEs was linked to a 30 percent decrease in the likelihood of becoming pregnant each month.
According to researchers, animal studies have linked high PDBE exposure with reduced thyroid function and altered levels of sex hormones, two possible explanations for why women with higher levels of PBDEs experienced a delay in becoming pregnant.
The good news about PBDEs? The chemicals—used as flame retardants for four decades and found in such common household products as foam furniture, electronics, fabrics, carpets, and plastics—are currently being phased out. In places like California, where the study took place, certain PBDEs have already been banned for use.
Researchers also note that all women in the study eventually became pregnant, even with high levels of PBDEs. The bad news? PBDEs are still found in products made before 2004 and may be widespread in household dust. Other studies have found that 97 percent of US residents have detectable levels of PBDEs in their blood and that the levels in Americans are 20 times higher than in their European counterparts (where the chemical is not in widespread use).