Flame Retardants Tied to Lower Birth Weights08/30/11
TUESDAY, Aug. 30 (HealthDay News) -- A flame retardant that was
phased out of use but is still present in older furnishings is
linked to lower birth weights in newborns of women exposed to it
during pregnancy, a new study suggests.
Evaluating levels of PBDEs -- or polybrominated diphenyl ethers
-- in blood samples of 286 pregnant women, researchers from the
University of California, Berkeley School of Public Health found
that every 10-fold increase was tied to a 4.1-ounce drop in the
birth weight of their babies.
"The good news is, these chemicals aren't being used anymore. But the bad news is, they're in things we don't replace very often," said study author Kim Harley, an adjunct assistant professor of maternal and child health and associate director of University of California Berkeley's Center for Environmental Research and Children's Health.
"Most of us are exposed to PBDEs and 97 percent of us have detectable levels," said Harley, adding that the research was the first large population-based study of its type.
In the United States and Europe, PBDEs were phased out of use in
new products in 2004, but they are still found in older foam
furniture, cars, high chairs, strollers, bedding and other goods.
The chemicals are not chemically bound into products, she said,
meaning they can leach into the environment.
The study, published Aug. 30 in the
American Journal of Epidemiology, found a shift toward lighter birth weights in women exposed to the chemicals. But Harley noted that very few babies in the study were born weighing less than 5.5 pounds, the threshold below which infants are considered low birth weight and more likely to suffer social and cognitive delays.
Most of the women were Latinas from low-income families who
participated in the Center for the Health Assessment of Mothers and
Children of Salinas (CHAMACOS) longitudinal study, which examines
environmental exposures and reproductive health in an agricultural
community. Earlier CHAMACOS research associated PBDE exposure to
reduced fertility and altered thyroid hormone function in
Although it was difficult to pinpoint why the flame retardant
would prompt lower birth weights, Harley said that anything that
affects thyroid hormone levels might compromise maternal weight
"If mothers don't gain as much, babies can be smaller," she said, adding that PBDEs are believed to be ingested orally rather than inhaled or absorbed, so stringent hand-washing and vacuuming can help control the chemicals' dispersal.
Jackson Morrill, director of the American Chemistry Council,
said the study's link between PBDEs and birth weight was no larger
than it might be due to chance once the authors implemented "proper
controls" in the research, including factoring in different
maternal weight gains or thyroid hormone levels. The authors also
noted such a limitation in their paper.
"The authors themselves noted that the effect of maternal weight gain . . . could impact the study's outcomes," Morrill said. "The negative associations were not statistically or clinically significant, meaning that they are unlikely to have implications for human health."
Harley acknowledged that such factors could skew study results
and that the study results should be replicated to confirm the
The authors also said that the PBDE levels in the women studied
were lower than those in the overall U.S. population. Women with
higher PBDE exposures might face a higher risk of delivering a low
birth weight baby, they said.
"Obviously, it's important that our homes are safe from fire," Harley said. "But we need to be aware of that balance."
The U.S. Environmental Protection Agency has more about
Copyright © 2011
. All rights reserved.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.