Yet Another Reason Not to Smoke in Pregnancy


DALLAS — Smoking during pregnancy is associated with overweight in the offspring, Dr. Nicholas Stettler reported at the annual scientific sessions of the American Heart Association.

His retrospective analysis of prospectively collected prenatal and postnatal data on 20,284 women who participated in the Collaborative Perinatal Project showed that after a host of potential confounding variables were controlled for, white women who smoked in pregnancy were 33% more likely than those who didn't to give birth to a child whose body mass index was at or above the 95th percentile at age 7 years. Black smokers were 39% more likely than nonsmokers during pregnancy to have an overweight 7-year-old, said Dr. Stettler of Children's Hospital, Philadelphia.

“In utero exposure to smoking may result in metabolic programming that leads to the development of obesity,” he said. “Smoking prevention and cessation in women of childbearing age may have unintended benefits, such as reduced risk for obesity in their offspring.”

The Collaborative Perinatal Project was conducted at 12 U.S. sites during 1959–1973. Of the participating mothers, 45% reported smoking during their index pregnancy. Among the potential confounders Dr. Stettler controlled for were maternal age, body mass index, and education level, along with the child's gender, birth weight, gestational age, birth order, and weight gain during the first 4 months of life.

The maternal smoking/overweight offspring association appeared to be dose dependent. For every 10 cigarettes per day a black woman smoked during pregnancy, the chances of her child being overweight at age 7 climbed by 21%. Similarly, the risk increased in white women by 18% for every 10 cigarettes per day smoked in pregnancy.

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