• Newborns delivered via caesarean-section (C-section) in the US have been swabbed with their mother’s vaginal fluids, full of important microbes, straight after birth in an attempt to boost their immunity in later life. (Getty Images)Source: Getty Images
Scientists in the US have tested whether swabbing infants born by caesarean-section with vaginal microbes straight after birth can increase a child’s immunity.
By
Yasmin Noone

2 Feb 2016 - 2:24 PM  UPDATED 3 Feb 2016 - 9:10 AM

Newborns delivered via caesarean-section (C-section) in the US have been swabbed with their mother’s vaginal fluids, full of important microbes, straight after birth in an attempt to boost their immunity in later life.

The world-first study, published in the journal Nature Medicine today, states that babies born by C-section lack the same exposure to microbiota – the community of microorganisms that inhabit the human body – that vaginally delivered babies have.

These microbes, present in vaginal fluids, perform an important role in immunity: they colonise the skin, oral cavity and gut of babies as they are born.

But now US-based scientists have shown that a C-section baby’s microbiome can be successfully modified if they are exposed to vaginal fluid as soon as they are delivered.

These microbes, present in vaginal fluids, perform an important role in immunity: they colonise the skin, oral cavity and gut of babies as they are born.

“From previous work we know that C-section delivery results in a very different microbiome in the newborn compared to vaginal delivery,” says lead author of the study, Assistant Professor of Genetics and Genomics and Medicine at Mount Sinai Hospital, Jose Clemente.

“We also know from epidemiological studies that C-section is associated with increased risks for some immune and metabolic conditions. Our hypothesis then is ‘can we lower the risks for those conditions if we restore the microbiome of C-section born babies’?

“This study demonstrates that we can partially do so during the first month of life.”

So how does it work? The ‘vaginal microbial transfer’ procedure was performed in a hospital under test conditions.Four infants were swabbed with gauze that had been incubated in their mother’s vagina for one hour prior to the C-section procedure.

The scientists then compared the babies’ microbiota to that of seven C-section–born infants not exposed to vaginal fluids and of seven infants born vaginally.

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Assistant Professor Clemente says although the transfer was not perfect – a few of the common microbes did not take hold – the experiment yielded positive results.

The team found that, 30 days after birth, the C-section–born infants exposed to vaginal fluids had a microbiota closer to that of vaginally born infants than to C-section–born infants not exposed to vaginal fluids.

“Before delivery, the baby is generally not exposed to microbes, so it’s thought this ‘first impression’ is important for the development of the baby,” member of the Icahn Institute at the Icahn School of Medicine at Mount Sinai, Assistant Professor Clemente tells SBS.

“In mouse studies, it has been shown that modifying their microbiome early in life can lead to significant consequences later on, for instance increased adiposity [levels of fat].

“In humans we do not have direct evidence, but there are several studies that link changes in the microbiome during childhood, through C-section [delivery] and antibiotic usage, with later risk of disease.”

Associate Professor of Medicine at University of Minnesota, Dr Alexander Khoruts, believes the study was an essential first step in future research into human immunity and disease prevention.

“Microbial communities are part of the human body,” says A/Prof Khoruts, who wrote an opinion piece accompanying the study.

There is a real concern that many practices introduced in recent history, including mode of delivery, use of antibiotics, premature interruption of breast feeding, various sanitation practices [etc] have impacted the composition of these human microbes.

“These are highly specialised and complex communities, adapted to live in partnership with humans.

“There is a real concern that many practices introduced in recent history, including mode of delivery, use of antibiotics, premature interruption of breast feeding, various sanitation practices [etc] have impacted the composition of these human microbes during the very sensitive developmental periods when the immune, nervous, and metabolic systems are being hardwired.”

He says some or all of these practices could contribute to increased prevalence of allergies, autoimmunity, obesity, autism, and many other health issues.

Both experts say that further long-term, randomised studies are required to determine the lasting effects of microbial exposure.

Assistant Professor Clemente also confirms that scientists will also soon test whether they can change the bacterial communities in C-section babies to be more ‘vaginal-like’ and lower the risk of some of the conditions associated with cesarean delivery.

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