Secondhand Smoke May Harm Fetus Like Smoking
Study Shows Passive Smoking Just as Risky as Smoking by Pregnant Women
WebMD News Archive
July 27, 2005 -- New research suggests that secondhand smoke exposure during
pregnancy may be just as damaging to the unborn baby as the mother herself
smoking during pregnancy.
Researchers pooled data from recent studies on genetic mutations in babies
linked to tobacco- smoke exposure. They found the risk of genetic mutations
associated with secondhand-smoke exposure was nearly identical to the risk tied
to maternal smoking during pregnancy.
"This analysis shows not only that smoking during pregnancy causes
genetic damage in the developing fetus that can be detected at birth, but also
that passive -- or secondary -- exposure causes just as much damage as active
smoking, and it is the same kind of damage," says researcher Stephen Grant,
PhD, in a news release. Grant is associate professor of environmental and
occupational health at the University of Pittsburg Graduate School of Public
"These kinds of mutations are likely to have lifelong repercussions for
the exposed fetus, affecting survival, birth weight and susceptibility to
disease, including cancer," says Grant.
New Warning for Secondhand Smoke
Researchers say the results of this study conflict with the three studies
from which they gathered their data. Those studies largely discounted the
effects of secondhand smoke on fetal development.
Each of the studies looked at the rates of mutation on the HPRT gene on the
X chromosome in umbilical cord blood samples from newborns.
In the study, published in the current issue of BMC Pediatrics,
researchers pooled data from all three studies and looked at the frequency of
the tobacco-smoke-induced genetic mutation as well as other mutations triggered
downstream by this mutation.
The reanalysis also included information on secondhand smoke exposure at
home, work, or in social situations among the "nonsmokers" used as
comparisons in the maternal smoking studies.
The study showed the increased rate of genetic mutations linked to
secondhand smoke exposure was "virtually indistinguishable" from the
rate linked to maternal smoking during pregnancy.
Stop Before Getting Pregnant
"Moreover, we found similarly increased induced mutations in women who
had quit smoking during pregnancy, usually when they found out they were
pregnant," says Grant.
"Perhaps, like certain pharmaceutical warnings, it would be appropriate
to caution women to quit smoking if they are pregnant or likely to become
pregnant. It is equally imperative that workplace protection be offered to
reduce passive exposure."