FRIDAY, Sept. 9, 2011 (HealthDay News) -- Researchers in Australia have developed a new treatment plan to reduce asthma flare-ups in pregnancy while minimizing drug exposure to developing fetuses.
This therapy tracks airway inflammation directly by measuring something known as "the fraction of exhaled nitric oxide" -- a marker of inflammation abbreviated as FENO -- in an exhaled breath. By doing so, researchers can identify asthma in pregnant women who have airway inflammation but no symptoms and tailor drug therapy accordingly.
In this study, researchers examined 220 non-smoking women with asthma who were less than 22 weeks pregnant. Half the women were treated based on their clinical symptoms during monthly visits (the control group) and compared to the women in the FENO group, who were tested for airway inflammation. The researchers found the flare-up rate among the women in the FENO group was roughly half that of those in the control group.
The reduction in flare-ups was associated with key changes in the women's asthma medications, including more frequent use of inhaled corticosteroid -- but at a lower total daily dose -- and earlier use of other drugs, such as long-lasting B2 agonists, the study authors said.
Medicating asthma based on a woman's symptoms alone can lead to either over-treatment or under-treatment of the condition, they added.
The study is published in the Sept. 9 European respiratory issue of The Lancet.
"Asthma management during pregnancy can be improved by the use of measuring FENO concentration and symptoms to adjust treatment. This algorithmic approach might also be beneficial for non-pregnant women with asthma," the authors wrote in a journal news release.
Meanwhile, a separate study in the same journal issue identified two new gene variants, linked to immune system signaling, that appear to boost a person's susceptibility for asthma.
By comparing the genetic information of thousands of patients with asthma with those of people without asthma, researchers from Australia identified two new genetic variants strongly associated with asthma risk.
One of the variants was found on the interleukin 6 receptor gene, which plays a key role in immunity and inflammation and is involved in the development of diseases such as rheumatoid arthritis.
The other variant, found on chromosome 11q13.5, was found to be more common in people with allergic asthma and atopic dermatitis (skin itching and dryness accompanied by a rash). This led the researchers to speculate that the variant might be involved in the development of allergic sensitization, which can increase a person's risk for allergic asthma.
The researchers pointed out, however, that asthma is a complex disease, and that many genes likely interact with a number of environmental risk factors to determine who will develop the condition.
More information
The U.S. Centers for Disease Control and Prevention provides more information on asthma.
