Vitamin C might help protect fetuses of smoking women.
Any woman who smokes knows that she should quit when she gets pregnant, but some women simply cannot or will not kick the habit, despite the known health risks to themselves and their fetuses.
About 12 percent of women keep smoking during pregnancy, despite public health campaigns and warnings from their doctors, leading to more than 450,000 smoke-exposed infants born each year in the United States, according to federal health statistics.
Those babies are at risk for premature delivery, growth retardation and death. Five percent to 10 percent of all fetal and neonatal deaths are blamed on smoking during pregnancy. Maternal smoking also can cause decreased pulmonary function and increased respiratory illness in offspring.
Now, researchers at Oregon Health & Science University have found that high doses of vitamin C may have the potential to counteract some of the negative effects that smoking has on unborn babies. They caution that their findings should not be construed to suggest that it's OK to smoke while pregnant.
"The single most important thing is for pregnant women to stop smoking," said Dr. Eliot Spindel, senior scientist in the neuroscience division at OHSU's Oregon National Primate Center and one of the study's authors.
`While this research finding may assist the babies of (smoking) mothers, it does not make smoking during pregnancy more acceptable,' he said. "It would only become a last resort treatment when an expectant mother is unwilling to stop smoking."
Nicotine, he said, is "incredibly addictive," and some women want to quit but can't.
The OHSU research, published Sunday in the American Journal of Respiratory and Critical Care Medicine, studied three small groups of infant rhesus monkeys.
Seven monkeys were born to mothers who received 2-milligram doses of nicotine daily, comparable with those of a smoking mother.
The breathing abilities and lung development of those monkeys were compared with seven monkeys born to mothers who had received both nicotine and 250-milligram doses of vitamin C daily during pregnancy. A third group of six monkeys received neither nicotine nor vitamin C and was studied as a control group.
The researchers found that animals exposed to nicotine before birth had reduced air flow in the lungs, compared with animals given nicotine and vitamin C, Spindel said.
Monkeys given nicotine and vitamin C had lung air flow close to that of a normal animal, he said.
Researchers also observed that increased levels of a protein called surfactant apoprotein B normally caused by nicotine were reduced by vitamin C.
Spindel said he doesn't know what mechanisms are causing vitamin C to have a protective effect against nicotine, but he has two theories.
One involves vitamin C's effect on connective tissues. Nicotine is known to be harmful to elastic tissues in the lungs, and it's possible that vitamin C may prevent that harm.
The other theory involves vitamin C's role as an antioxidant, protecting molecules in the body from damage by free radicals that are generated during normal metabolism and from exposure to toxins and pollutants.
While the study demonstrates vitamin C's promise for counteracting the effects of nicotine on lung function, researchers note that vitamin C did not counteract other negative effects of smoking during pregnancy, such as abnormal brain development and decreased body weight.
Also, the researchers said that more research is needed to determine the appropriate dosage for humans, and to demonstrate that giving pregnant women higher levels of vitamin C will not itself cause development problems.
Spindel said that if he were an obstetrician, he first would work hard to get a pregnant patient to quit smoking. If that failed, he probably would encourage the woman to take an additional 100 to 250 milligrams of vitamin C each day, in addition to a neonatal vitamin, which has 100 milligrams of vitamin C.
Those extra milligrams probably would be safe and might be beneficial, he said, but the research indicates that it will not prevent the effects of nicotine in fetal brain development or fetal growth, nor will it prevent the potential for premature delivery.
Still, one expert in high-risk pregnancies who was not involved in the study said that the findings will change the way he takes care of pregnant women who smoke.
Dr. Michael Gravett, chief of maternal-fetal medicine at the OHSU School of Medicine, said that if he can't get his pregnant patients who smoke to quit, he plans to start telling them to take vitamin C.
The monkeys used in the study are very similar to humans during pregnancy, with the same type of placenta and a long gestational period, he said.
What he found interesting about the study was that it showed that smoking had a much more adverse effect on fetal development than was previously thought.
The new study showed that the mothers' smoking caused changes in their babies' lungs. This fits in with a new area of study in obstetrics called fetal origin of adult disease - or "you are what your mother ate," Gravett said. For example, fetuses that are nutritionally starved are more likely to develop heart disease and diabetes as adults, he said.
"What happens to you as a fetus is extraordinarily important as to what diseases you may be susceptible to as an adult," he said.
The new study found that the baby monkeys had significant changes in their lungs, which could predispose them to heart disease or lung disease later in life, Gravett said.
Tim Christie can be reached at 338-2572 or firstname.lastname@example.org.
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|Title Annotation:||Health; An Oregon Health & Science University study finds that large doses aid lung function|
|Publication:||The Register-Guard (Eugene, OR)|
|Date:||May 2, 2005|
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