Babies born via Cesarean section have a different microbiome than infants delivered naturally: For having skipped that trip down the birth canal, C-section babies lack bacteria that help the immune system recognize and accept other beneficial microbes; they may also be at an increased risk for obesity, asthma, allergies, and autism. "What we don't know is if the reason the risk is greater is because of the difference in the microbiome," UC San Diego scientist Rob Knight tells the Los Angeles Times. Knight and his team may have found a way to eliminate the risks with a simple swipe. First, they recruited 18 babies and their mothers. Next, immediately after birth, they swiped four C-section babies with gauze held in the mother's vagina. Over the next month, the microbiome of the four infants was found to be more similar to that of babies delivered vaginally than other C-section babies.
They weren't identical, though. "For some taxa the transfer was essentially complete, but other taxa didn't really take," Knight says. A gastroenterologist not involved in the study tells Smithsonian that the babies' gut microbes "look much more like a C-section baby's than a vaginal birth baby's." Knight admits it's not clear how the transfer might affect the long-term health of the C-section babies, but an expert tells the New York Times the study is "extremely important" for the sole fact that it shows such a transfer is possible. Knight and his team are now planning a larger study that will follow a greater number of babies for a longer period. In the meantime, they warn that the mothers who took part in the study underwent "a number of tests to make sure it is a safe procedure … The take-home message would be don't do this at home." (C-sections are rampant in this country.)