Smokers born to women who smoked during pregnancy may have a harder time quitting than those whose mothers abstained from smoking while pregnant, according to researchers at Duke University Medical Center.

In experiments conducted at the Duke Center for Nicotine and Smoking Cessation Research, scientists found that rodents exposed to nicotine before birth self-administered more of the drug after a period of abstinence than rats that were not exposed in utero to nicotine. The researchers concluded that to lower the risk of addiction among their children, pregnant women should not only avoid smoking but also the use of smoking-cessation products that contain nicotine.

"Smoking during pregnancy can harm the baby in ways that extend far beyond preterm delivery or low birth weight," said researcher Edward Levin, Ph.D. "It causes changes in the brain development of the baby that can last a lifetime."

"It is easy to quit smoking -- anyone can do it, for a brief time," Levin added. "But not taking it up again -- that is the part that has proven so difficult for most people, especially those who have been exposed to nicotine before birth."

Philip Morris and the National Institute on Drug Abuse funded the research.

The study was published in the November 2006 issue of the journal Pharmacology, Biochemistry and Behavior.