From: Editor, ENN
Approximately 8 out of every 1,000 newborns have congenial heart
defects — abnormalities in the heart’s structure that happen due to
incomplete or irregular development of the fetus’ heart during the
first stages of the mother’s pregnancy. While some are known to be
associated with genetic disorders, the cause of most of these heart
defects is unknown.
However, according to research presented at the American Heart
Association’s Scientific Sessions 2013, heart defects in children may
be associated with their mothers’ exposure to specific mixtures of
environmental toxins during pregnancy.
Researchers examined patterns of congenital heart defects incidence
and presence of environmental toxicants in Alberta, Canada. The
ongoing research seeks to determine if pregnant women’s proximity to
organic compounds and metals emitted in the air impacts the risk of
heart defects in their children.
“Although still in the early stage, this research suggests some
chemical emissions — particularly, industrial air emissions — may be
linked to heart abnormalities that develop while the heart is forming
in the womb,” said lead researcher Deliwe P. Ngwezi, M.D., a Ph.D.,
student and research fellow in pediatric cardiology at the University
of Alberta in Canada.
The study is based on congenital heart defects diagnosed in 2004-11
and chemical emissions recorded by a Canadian agency tracking
pollutants.
Researchers looked at three chemical categories, but only one group
showed a strong correlation with rates of congenital heart defects.
According to Ngwezi, the group of chemicals consists of a mixture of
organic compounds and metals namely: benzene, butadiene, carbon
disulphide, chloroform, ethylene oxide, hexachlorobenzene,
tetrachloroethane, methanol, sulphur dioxide, toluene, lead, mercury
and cadmium.
Congenital heart defect rates have gradually decreased in Canada since
2006, which is about the time the government tightened regulations to
reduce industrial air emissions, Ngwezi said. The heart defect
decreases were mainly associated with heart defects resulting in holes
between the upper and lower heart chambers (septal defects) and
malformations of the cardiac outflow tracts (conotruncal defects),
according to Ngwezi.
“For now, consumers and healthcare providers should be educated about
the potential toll of pollutants on the developing heart,” she said.
“As we have observed in the preliminary results, when the emissions
decrease, the rates of congenital heart defects also decrease.”
This study, she said, should draw attention to the increasing evidence
about the impact of environmental pollution on birth defects.
Limitations of the study include that researchers’ observations were
made at a group level, not according to individual risk and the
self-reported industry data which is monitored and collected annually
by government, according to Ngwezi.- Environmental News Network
