Mothers who smoke cigarettes during pregnancy double their children’s chances of developing asthma before their fourth birthdays. And the more a pregnant mother smoked, the higher her child’s chance of developing asthma in the first few years of life. Smoking also increases the child’s chances of developing allergies at a young age.

A new report from Sweden’s Karolinska Institutet’s medical university describes a study that delved deeper into the effects of tobacco smoking on unborn children and on children exposed to tobacco smoke in the first few months after birth. Their findings reveal secondhand, or passive, smoke in the child’s environment also increases the child’s chance of developing asthma. It can trigger allergies, too.

At the age of 4, toddlers who had been exposed to tobacco smoke when they were only two months old had allergy antibodies in their bloodstreams in greater number than 4-year-olds who had been in a nonsmoking environment at the age of two months. Some of the children in the smoking environment were found to have antibodies against more than one allergen, with antibodies for cat allergies being twice as likely in children exposed to smoke than those who had not been so exposed.

The study forms the basis of the doctoral thesis of Dr. Eva Lannero, who led the study on tobacco smoke and children’s health. Lannero has expressed particular concern over the cat allergies, which she says are everywhere and difficult to avoid. Allergies are often seen as warning signs of chronic asthma developing as the child grows.

To gauge smoking with a mother’s education level, 7% of the college-educated study participants said they smoked during pregnancy. Of those who had not completed the US-equivalent of a high school education, 20% reported smoking during pregnancy. Smoking is more common in less-educated people around the world.

The mothers in the survey gave birth between 1994 and 1996, giving the research team 4,100 children to monitor for the study. The children, monitored since birth, are part of an on-going study to explore the ways a child’s asthma and allergies are influenced by environmental factors.

Source: Karolinska Instituet