Children whose mothers smoked during pregnancy have an increased risk for developing asthma, a respiratory disease that causes wheezing, chest tightness, and airway inflammation. In addition, the risk of asthma also appears to be elevated in children whose grandmothers smoked during their pregnancies, say researchers from the University of Southern California in Los Angeles.
The mothers of 338 children under 5 years of age with asthma reported how many cigarettes they'd smoked during pregnancy, whether they'd quit smoking after giving birth, and whether there were other smokers in the household. In addition to answering questions about their own smoking habits, moms answered the question "Did your mother smoke when she was pregnant with you?"
Several factors were associated with an increased risk of asthma. Being born prematurely and having family members with asthma increased a child's risk of developing the disease before 5 years of age.
Exposure to smoke also affected a child's risk of developing . Most moms who smoked at the beginning of pregnancy continued to smoke throughout pregnancy. Twenty-three percent of moms smoked before pregnancy, 19% of moms smoked during the first trimester, 13% of moms smoked during the second trimester, and 12% of moms smoked during the third trimester. And after birth, about 30% of the children were exposed to secondhand smoke at home.
Children whose mothers smoked during pregnancy had an increased risk of asthma. In addition, mothers of children with asthma were more likely to have been exposed to smoke during their own mothers' pregnancies - compared to the moms of kids who didn't have asthma. Even kids whose moms didn't smoke - but whose grandmothers did - had an increased risk of developing asthma. Although it's not exactly clear why this happens, the researchers in this study think that somehow exposure to tobacco products may alter DNA patterns in a developing fetus. This alteration could affect immune system function and increase a future generation's susceptibility to asthma.
There's good news for women who quit smoking prior to pregnancy, though: Researchers found that the children of mothers who quit smoking before pregnancy had an asthma risk similar to children whose mothers never smoked.
What This Means to You: According to the results of this study, children whose mothers or grandmothers smoked during pregnancy have an increased risk of developing asthma. Fortunately, reducing your child's exposure to smoke is something you can control. The best way to protect your baby's health - and your own - is to avoid smoking before, during, and after pregnancy. If you do smoke, talk to your doctor or obstetrician about how to quit.
Source: Yu-Fen Li, PhD, MPH; Bryan Langholz, PhD; Muhammad T. Salam, MBBS, MS; Frank D. Gilliland, MD, PhD; Chest, April 2005
Reviewed by: Steven Dowshen, MD
Date reviewed: May 2005
