Washington: Brominated flame retardants, the
chemicals found in household items like furniture cushions and
carpet pads, can alter thyroid hormones in pregnant women that
may hamper the baby`s growth and brain development, a new
study has claimed.
Flame-retarding chemicals known as polybrominated
diphenyl ethers, or PBDEs, are a class of toxic chemicals in
wide use to prevent the spread of fire.
Earlier research suggested that 97 per cent of Americans
get exposed to PBDE which causes an array of adverse health
effects including thyroid hormone disruption.
The new study, published in the journal Environmental
Health Perspectives, is considered important because it is the
first human research showing a link between the ubiquitous
chemicals and altered levels of the hormones in pregnant
Though its effects on babies are unknown, researchers
said it might lead to smaller foetuses, and reduce children`s
intelligence and motor skills.
"Normal maternal thyroid hormone levels are essential for
normal foetal growth and brain development, so our findings
could have significant public health implications," said lead
researcher Jonathan Chevrier of the University of California,
"These results suggest that a closer examination between
PBDEs and these outcomes is needed."
Brenda Eskenazi, the co-author of the study, said despite
the prevalence of these flame retardants, there are few
studies that have examined their impact on human health.
"Our results suggest that exposure to PBDE flame
retardants may have unanticipated human health risks."
For their study, the researchers analysed blood samples
from 270 women taken around the end of their second trimester
They measured concentrations of 10 PBDE chemicals, two
types of thyroxine (T4) and thyroid-stimulating hormone (TSH).
They controlled for such factors as maternal smoking, alcohol
and drug use, and exposure to lead and pesticides.
The analysis focused on the five PBDE chemicals that
were detected most frequently and are components of a mixture