Meanwhile, Ly and her colleagues explored similar risks associated with Caesarean sections by analyzing the cellular immune regulatory activity present (in the form of so-called treg cells) in the umbilical cord blood of 50 babies born by Caesarean and 68 babies delivered vaginally. All the babies had a least one parent with allergies and/or asthma.
The authors found that among C-section babies, treg cells were more likely to fail to operate properly, raising the risk for the early onset of immune system disruption. This, in turn, may increase the likelihood that a child could grow up to develop an allergy or asthma.
Ly and her team said that the suggestion that the manner of delivery could actually influence immune system development and ultimately asthma/allergy risk could be due to the fact that vaginal labor provides beneficial exposure to birth canal microbes that simply aren't available to a C-section baby.
"But still I think it's important to reiterate that while this is interesting research, it is a small study and the first of its kind," noted Ly. "So there is much more follow-up work that needs to be done to see if these newborns in fact start developing symptoms of asthma or allergies as they grow."
Approaching the root causes of asthma and allergies from yet another angle, a third team of German researchers presented findings suggesting that mothers who visit farms and drink farm milk confer a anti-allergy benefit to their future babies.
The study involved 18 farming mothers and 59 non-farming mothers. Farm-based mothers appeared to give birth to babies with better-functioning treg cells.
For details on childhood asthma, visit the American Lung Association.
SOURCES: Wilfried Karmaus, M.D., professor, department of epidemiology and biostatistics, University of South Carolina, Columbia, S.C.; Ngoc Ly, M.D., assistant professor, pediatrics, University of California at San Francisco; May 21, 2008, presentations, American Thoracic Society International Conference, Toronto