Kids More Apt to Smoke If Mom Did While Pregnant

May 20 -- TUESDAY, May 19 (HealthDay News) -- Smoking while pregnant "biologically primes" the unborn child to become a regular smoker as a teen and young adult, according to a theory put forth by University of Arizona researchers.

"Somehow smoke is changing the brain chemistry," said the lead researcher, Dr. Roni Grad, an associate professor of clinical pediatrics at the university.

"If you are exposed to smoking prenatally or in the early years of life, you are much more likely to be a chronic smoker at the age of 22," Grad said.

In fact, these children are four times more likely to become regular smokers, according to the research, which was to be presented May 19 at the American Thoracic Society's international conference in San Diego.

For the study, Grad's team used data from the Tucson Children's Respiratory Study to see whether a mother's smoking during pregnancy and during her child's early years affected whether the child smoked later on.

The researchers assessed maternal smoking during pregnancy and when infants were 1.5 months and 1.5 years old and again when the children were 6, 9 and 11 years old. They then looked at the children's smoking behavior when they were ages 16 and 22.

They found that women who smoked during pregnancy and during their children's early years were more likely to have kids who smoked at age 22. This proved true whether the mother smoked or did not smoke during the child's school years.

In addition, the children of mothers who smoked during pregnancy and their early years were less likely to quit smoking than were the offspring of mothers who never smoked or who started smoking when their children were school-age.

The impact of early maternal smoking was not affected by whether the children's fathers smoked or by peer pressure during adolescence, the study found.

"Nobody should smoke," Grad said. "I would definitely discourage any mother from smoking around her child. If children have been exposed in early life to smoke, I would really go the extra mile to try to keep them from experimenting, because they may be at higher risk of becoming nicotine dependent very quickly."