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Smoking During Pregnancy Increases
Risk as Well
Although women who undergo amniocentesis in pregnancy have a slightly
increased risk of having an infant with clubfoot, new study findings suggest
that having the test just a few days later in pregnancy can reduce this
risk.
Dr. G. Yoon and colleagues at the University of Calgary looked at 4,464
amniocentesis procedures performed between 11 and 19 weeks of pregnancy
over a 4-year period.
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When the amniocentesis was performed between week 11 to just before
13 weeks, 1.1% of children were born with the foot abnormality.
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When the test was done during week 13 but before week 15, only 0.4%
of children were born with the abnormality.
- When the test was performed from week 15 to just before 20 weeks,
the rate declined even further, to 0.1%.
The study excluded patients with any abnormality, infection or multiple
pregnancy, in hopes of avoiding pre-existing conditions that might predispose
to foot abnormalities.
In amniocentesis, a needle is used to withdraw a sample of the fluid
surrounding the fetus, which is used to perform prenatal tests.
Nobody is quite sure why amniocentesis increases the risk of clubfoot
deformities
Meeting of the American Society
of Human Genetics October, 2000 Philadelphia, PA
Pregnant Smokers Up Risk of Clubfoot
Pregnant women who smoke may increase their child's
risk of clubfoot up to 20-fold, according to a new study.
Researchers compared 346 infants with clubfoot
with 3,029 infants without the condition who were born between 1968 and
1980.
"This study provides further evidence that
both maternal smoking and family history are important risk factors for
clubfoot and identifies a potentially important interaction between these
two variables," researchers conclude.
American Journal
of Epidemiology October 1, 2000;152:658-665
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