Women who are exposed to flame retardants during pregnancy may be lowering their kids' IQs, researchers have found.

The findings, published in the journal Environmental Health Perspectives, details how there was a 10-fold increase in polybrominated diphenyl ether (PBDE) concentrations, a type of flame retardant, in early pregnancy.

Given that this stage of development is when a child's brain is growing, researchers noticed a 4.5 IQ decrement. This impact is equivalent to toxic environmental lead exposure.

PBDEs have been widely used as flame retardants in furniture, carpet padding, car seats and such the past three decades. While most consumer items containing PBDEs were voluntarily removed from the market 10 years ago, some are still in circulation. Nearly all homes and offices still contain some PBDEs, and a recent study pointed to the fact that most furniture in preschools and child daycare settings contains flame retardants.

To gauge the effect these harmful substances have on future children, researchers from Simon Fraser University followed the levels of PBDEs in 309 US women at 16 weeks of pregnancy, and followed their children to the age of five.

"The results from this and other observational human studies support efforts to reduce Penta-BDE exposures, especially for pregnant women and young children," professor Bruce Lanphear said in a statement. "Unfortunately, brominated flame retardants are persistent and North Americans are likely exposed to higher PBDE levels than people from other parts of the world. Because of this it is likely to take decades for the PBDE levels in our population to be reduced to current European or Asian levels."

That's not to say that officials aren't trying to reduce people's exposure to flame retardants. The United Nations Environment Program added two of three existing commercial PBDE formulas to the list of banned Persistent Organic Pollutants due to concerns over toxicity in wildlife and mammals in 2009.