Smoking in pregnancy has long-lasting impact

A new study using laboratory rats provides strong evidence that smoking during pregnancy can have lasting harmful effects on the developing heart.

Scientists from the Center for Perinatal Biology, Loma Linda University, California found that adult offspring of laboratory rats who were exposed to nicotine prenatally showed clear signs of heart dysfunction.

"Our study shows that prenatal...nicotine has significant impact on cardiac function of adult offspring," Dr. Lubo Zhang told Reuters Health.
"The finding supports a very exciting area of research called 'fetal programming of cardiovascular disease.' This occurs not only with nicotine but with many other insults that may occur during fetal development," Zhang said.

In the study, the Loma Linda team treated rats with nicotine while they were pregnant and up to 10 days after delivery. The researchers then assessed the cardiac function of 3-month old male and female offspring.

Zhang's group observed that prenatal nicotine treatment significantly decreased coronary blood flow in adult female offspring.

In both male and female offspring, prenatal nicotine exposure significantly increased the susceptibility of the heart to injury. Again, the effect of nicotine was more pronounced in females than in males. "At the moment, we don't know why there is this gender dichotomy with females being more susceptible than males," Zhang said.

An estimated 11 percent of American women smoke during pregnancy. The harmful effects of nicotine exposure to their fetuses and newborns are significant. For example, a 2004 report found that women who smoked during pregnancy had children who were much higher risk for sudden infant death syndrome. The new study shows that smoking during pregnancy can lead to heart and vascular dysfunction beyond the formative years and into adulthood.

Zhang presented his research at the American Physiological Society's 120th annual meeting, part of Experimental Biology 2007, which is underway in Washington DC.