MedWire News: Children born to women who smoke during or after pregnancy face an increased risk of developing asthma-like symptoms and allergies, Swedish research shows.

Dr Eva Lannerö, from the Karolinska Institute in Solna, studied data on the incidence of wheezing and allergic sensitisation among 3619 children who were monitored from birth until the age of 4 years.

The children's parents completed questionnaires on various lifestyle factors, including smoking habits during pregnancy and in the first 2 months after delivery.

Information on exposure to environmental tobacco smoke was also collected when the children were aged 1, 2, and 4 years.

Dr Lannerö found that children born to women who smoked during pregnancy were more than twice as likely to suffer from recurrent wheezing and 1.8 times more likely to suffer from transient wheezing by the age of 4 years than those with mothers who did not smoke during pregnancy.

Analysis also revealed that children who were exposed to environment tobacco smoke in early life were 1.3 times more likely to become sensitised to allergens than those without such exposure.

The effect of environmental cigarette smoke on sensitization to cat allergens was particularly strong, with children exposed to tobacco smoke being twice as likely to develop allergic sensitivity as those who were not exposed.

"This is particularly worrying as cat allergens are almost everywhere and are hard to avoid," said Dr Lannerö.

She concluded: "Our data indicate that exposure to maternal cigarette smoking [in the womb] is a risk factor for wheezing up to 4 years of age, and exposure of infants to environmental cigarette smoke increases the risk of... sensitization to indoor inhalant and food allergens."

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