Asthma is a long-term lung disease that inflames and narrows the airways, causing significant episodes of wheezing, chest tightness, shortness of breath, and coughing. Children born to women who smoke, either during pregnancy or afterwards, are at increased risk for developing asthma.
To look at the effects of smoking during pregnancy across generations, scientists supported by the Pregnancy and Perinatology Branch administered nicotine to pregnant rats. Then they measured the lung function in the child rats, the grandchildren rats, and the great-grandchildren rats. None of the descendants (children, grandchildren, or great-grandchildren of the original rats) were exposed to any additional nicotine.
Nonetheless, the researchers found that the subsequent generations of rats had reduced lung function, similar to that found in asthma. The effect was strongest for male descendants compare with females. The study showed that the increased risk of asthma from smoking during pregnancy can be conveyed through generations (PMID: 23106849).