Smoking and placental injury.
It's well known that smoking during pregnancy isn't good for growing fetuses. Researchers at the University College in London now understand why.
"The profound effects of smoking on fetal development are irreversible and may cause impairment in the health and well-being of the offspring in later life," said Dr. Peter Hindmarsh, the lead researcher. "In particular, the reduced brain size that we saw in smokers' babies could lead to impaired cognitive ability of the child."
The researchers looked at two factors--blood flow between the fetus and the placenta and the umbilical cord levels of insulin-like growth factors (IGF). The impact of the first factor, fetal-placental blood flow, is fairly obvious. Less blood flow results in poorer fetal nutrition and decreased growth. Smoking damages the placenta, resulting in decreased blood flow.
IGF are essential for fetal growth and organ development. The umbilical cord levels of IGF were inversely related to the number of cigarettes the mother smoked. For example, in non-smokers the IGF levels averaged 70.2 nanograms/milliliter. In women who smoked 20 or more cigarettes per day, the average levels fell to 60.7.
Dr. Hindmarsh stated, "What we're talking about are reductions of about 10-15% (of IGF levels), producing rather similar reductions in overall birth size, birth length, and head growth." There are long-term consequences to low birth rate-increased risk of adult hypertension, diabetes, and infertility.
The babies whose mothers quit smoking as soon as they learned they were pregnant had normal placental function, normal levels of IGF, and were of normal size. "This shows it is worth thinking about stopping, because even in a very short time like pregnancy you aren't going to set the baby up for the same sort of problems as if you persist," said Dr. Hindmarsh.
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|Author:||Sagall, Richard J.|
|Publication:||Pediatrics for Parents|
|Article Type:||Brief Article|
|Date:||Jul 1, 2003|
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