Smoking During Pregnancy Shows Mixed Effects

Smoking during pregnancy appears to affect children’s birth weight, and possibly their risk of becoming overweight, but it may not directly harm other aspects of physical and cognitive development, a large study suggests.

The findings, from a study of nearly 53,000 U.S. children born in the 1960s, found that those whose mothers smoked during pregnancy were at higher risk of low birth weight — a link that studies have long noted.

There was also evidence, albeit weaker, that these children were more likely than children of non-smoking women to be overweight by age 7.

Some past studies have found this link as well, though researchers can only speculate on the reasons; one theory is that nicotine may affect the fetal brain in a way that influences appetite control later in life.

On the other hand, the current study also found that mothers’ smoking did not appear to directly affect other aspects of their children’s development — including intelligence, school performance and the risk of behavioral problems.

An initial look at the data did show associations between smoking during pregnancy and various developmental problems.

But those links disappeared when the researchers factored in the family environment — such as parents’ income and education, and whether the child lived with both parents.

Read more at Reuters