Smoke exposure late in pregnancy might boost baby's eczema risk

(HealthDay) -- A mother's exposure to tobacco smoke during the last three months of pregnancy may increase the risk that her child will develop the allergic skin condition eczema during infancy, a new study suggests.

The study authors pointed out that it is already known that children whose mothers were exposed to tobacco smoke during pregnancy are at a higher than normal risk for developing asthma or respiratory infections. However, previous studies regarding the relationship between smoke exposure and eczema risk came up with mixed results.

To investigate the potential connection, the research team focused on more than 1,400 infants between the ages of 2 months and 18 months.

The children's families provided information on their history of allergic diseases and the level of environmental tobacco smoke exposure during pregnancy and thereafter. The investigators also noted all cases of eczema, which is characterized by red, itchy skin.

The team found that eczema rates were significantly higher among children who had been exposed to smoke during their mother's third trimester than among children who had no smoke exposure. No such increase in eczema risk was observed among children whose mothers were exposed to smoke during the first trimester. Similarly, no increased risk was noted among infants exposed to smoke in the first six months following birth and beyond.

"Tobacco smoke exposure during the third trimester seems to affect the development of the immune system in the offspring, which in turn facilitates development of eczema after birth," the study's senior author, Dr. Kenji Matsumoto, said in a news release from the American Academy of Allergy, Asthma & Immunology. "This also raises questions of whether or not tobacco smoke exposure may affect the innate immune responses of the skin."

Matsumoto and colleague Dr. Miwa Shinohara are scheduled to present the study findings Saturday during a meeting of the American Academy of Allergy, Asthma & Immunology in Orlando, Fla.

Researchers note that the study does not show that smoke exposure in the last trimester causes eczema, merely that an association between the two was found.

Data and conclusions presented at medical meetings should be considered preliminary until published in a peer-reviewed medical journal.

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