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‘Vaginal seeding’ birthing trend may not be safe, doctors warn

Several large epidemiological studies have reported that babies born by Caesarean section are at an increased risk of obesity, allergies, asthma and autoimmune diseases.

In an editorial published this week in the BMJ, physicians from the United Kingdom and Australia issued a strong cautionary note about one of the latest birthing trends: “vaginal seeding.”

The practice puts babies at risk of developing serious infections, they warn, and therefore should be avoided until research determines whether it’s safe.

Parents, including those in the U.S., are increasingly requesting that their ob-gyn perform vaginal seeding, also known as microbirthing, when their baby is born by Caesarean section. Or they are doing it themselves. The “seeding” involves swabbing the mother’s vaginal fluid over the newborn’s mouth, eyes, face and skin.

Parents hope that by exposing the baby to bacteria from the birth canal, they will boost the child’s immune system and ward off future health problems associated with a Caesarean birth.

Several large epidemiological studies have reported that babies born by Caesarean section are at an increased risk of obesity, allergies, asthma and autoimmune diseases. Other studies have suggested a link between these same medical conditions and the types of microorganisms present in the body.

“The theory is that by transferring bacteria from mum to baby, these bacteria can then make their way to the baby’s gut and alter the bacteria in their tummy — called the microbiome,” said Dr. Aubrey Cunnington, a specialist in pediatric infectious diseases at Imperial College London and one of the authors of the BMJ editorial, in a released statement.

In theory only

“There is now quite a lot of evidence that differences in the microbiome are associated with risk of developing conditions such as allergies and obesity,” he added. “However people have made a leap of logic that gut bacteria must be the link between caesarean section and risk of these diseases. But we just don’t know this for sure — or whether we can even influence this by transferring bacteria on a swab from mum to baby.”

Only one clinical trial is currently investigating vaginal seeding, Cunnington and his editorial co-authors point out, and that study is designed to determine only if vaginal bacteria can be successfully transferred to newborns through “seeding,” not if the practice is either safe or effective.

That study is also using tests to exclude women who might be carriers of pathogens that would put their infants at risk of infection, such as group B streptococcus, herpes simplex virus, Chlamydia trachomatis and Neisseria gonorrhea. These infections often produce no noticeable symptoms and are not always tested for in pregnant women, the editorial points out. Women who swab their babies with vaginal fluid, therefore, may not realize they are passing one of these pathogens onto their baby.

Up to 30 percent of pregnant women, for example, are estimated to be carriers of group B streptococcus — usually without any symptoms. This bacterium is the leading cause of a sepsis, a serious blood infection, in infants.

“One colleague had to intervene when a mother with genital herpes, who had undergone a caesarean section, was about to undertake this process,” said Cunnington. “Swabbing would have potentially transferred the herpes virus to the baby.” 

Of course, these same infections can be passed on to the baby during vaginal birth. But pediatricians are alert to that possibility when parents bring an ill baby to them. Doctors do not expect to see such infections in babies born via Caesarean section, and therefore a correct diagnosis may be delayed. 

Risk not justified

Cunnington and his colleagues advise doctors not to perform vaginal seeding until more is known about both the effectiveness and the safety of the procedure.

“We believe the small risk of harm cannot be justified without evidence of benefit,” they write.

The editorial’s writers also recognize, however, that the simplicity of the procedure means many parents will just go ahead and do it themselves. They therefore urge  parents to first fully educate themselves about the risks, and, if they do decide to “seed” their baby, to make sure they tell their pediatrician about it.

“Parents and health professionals should also remember that other events in early life, such as breast feeding and antibiotic exposure, have a powerful effect on the developing microbiota,” Cunnington and his colleagues add. “Encouraging breast feeding and avoiding unnecessary antibiotics may be much more important than worrying about transferring vaginal fluid on a swab.”

FMI: You can read the editorial in full at the BMJ website.

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