According to a new study, women found to have higher blood levels of flame retardants or polybrominated diphenyl ethers (PBDEs) to be found in certain household objects, take longer than women with lower levels to fall pregnant.

The women who had slightly lower concentrations of PBDEs than the general U. S. population, researchers speculate could be because many of them grew up in Mexico, where PBDE exposure is limited.

The study which has been published online in the Environmental Health Perspectives reveals, for every tenfold PBDE increase in the blood, there was a 30% to 50% decrease in the chances of falling pregnant in any given month.

However, an industry spokesperson indicated the study findings to be limited, as environmental levels of PBDEs, no longer used in new production are expected to decline over time.

The implementation of new fire safety standards in the United States in the 1970s led to PBDE compounds to be commonly found in foam, carpets, furniture, plastic, electronics and other household items.

Other studies indicate 97% of Americans have detectable PBDE levels in their blood, 20% higher than to be found in Europeans. As well due to strict fire laws in California, people from the state have been found to have the highest exposure to these chemicals.

For the study, lead researcher Kim Harley and colleagues interviewed 223 pregnant women from northern California, to find out how long it took them to become pregnant, including measuring PBDE levels in blood samples taken close to the end of their second trimester. They found 3 to 1,200 nanograms per gram of fat of PBDEs in their blood.

Those with a higher exposure to the flame retardant took longer to fall pregnant and the higher the levels, the longer it took for them to conceive.

For example, the researchers found three months to be the median time, with 15% taking over 12 months to conceive, while some took 10 years or more.

PBDEs are to be found in the highest concentration of four types of penta-BDEs, whose production along with octa-BDEs was stopped in 2004. However, older products still retain the chemicals, which compounds being chemically unbound can leach out of products.

Experts believe they disrupt thyroid functioning, and as is known low and high thyroid levels alter normal menstrual patterns, thus affecting fertility.

The study has been found to be scientifically sound, as researchers controlled for other factors affecting fertility like exposure to pesticides, irregular menstrual cycles, frequency of intercourse, weight, use of birth control pills in the year before conception, smoking, and alcohol and caffeine use.

Even so, a representative from the flame retardant industry taking exception to the findings said the study is limited to penta and octa-(PBDEs) and does not include deca, the only PBDE in use, currently.

The best way to reduce PBDE exposure is to reducing exposure to house dust i. e. wet mopping or vacuuming with a filtered vacuum cleaner, including washing your hands frequently.