Infants that are born by Caesarian section have higher rates of allergies, asthma, and obesity than infants delivered vaginally, and some suggest that differences in the microbiomes they receive at birth could be the cause.
A recent study in Nature Medicine from the University of California, San Diego's Rob Knight and his colleagues examined how swabbing babies born by Caesarian section with their mother's vaginal microbe — which they would've been exposed to had they been born vaginally — affected the development of their microbiomes. They reported that such swabbing could partially restore the microbiomes of babies delivered by C-section.
An editorial in BMJ in February, though, cautioned clinicians against trying this approach until it has been further studied. "It might seem reasonable to perform this simple and cheap procedure, even without clear evidence of benefit, but only if we can be sure that it is safe," physicians from the UK and Australia write.
But, they add, it has not yet been shown to be safe. Further, they point out that babies "may develop severe infections from exposure to vaginal commensals and pathogens, which the mother may carry asymptomatically."
In The Scientist last week, UCSD's Knight and the University of Chicago's Jack Gilbert write that they agree that " we don't yet know whether the many conditions associated with C-section … are due to lack of exposure to the maternal vaginal microbiome."
Still, they add that if parents want to do the procedure themselves — provided that the mother is free of pathogens that could harm the infant — that should be their choice.