Faecal transplant in C-section babies could ward off asthma, scientists suggest

Alexandra Thompson
·5-min read
Mother feeding asian baby with bottle of milk, banner copy space
A faecal microbiota transplant, administered via expressed breast milk, could boost gut bacteria in babies born by C-section. (Posed by models, Getty Images)

Scientists may have come up with a novel, if slightly nauseating, way of warding off asthma among newborns delivered by C-section.

Babies born non-vaginally are known to be at an increased risk of asthma and allergies in later life. This is thought to be due to them missing out on the “good bacteria” in their mother’s vagina, which helps strengthen the immune system.

Infants born naturally are also exposed to the “microbial material” in faeces that lurk on a woman’s perineum, the space between the anus and the genitals.

To compensate for C-section’s shortcoming, scientists from the University of Helsinki proposed feeding newborns a small amount of diluted maternal faeces via breast milk.

Read more: Crohn’s could be treated via freeze-dried faeces capsules

A proof-of-concept study suggests the procedure can be safe, providing stringent screening is carried out beforehand. It also revealed the C-section babies had a similar microbial make-up at three months old to those born vaginally.

The scientists were encouraged by their “effective” results, but stressed new mothers should not try this at home.

a Young pregnant woman lays on the operating table moments before a caesarean section
C-sections mean newborns are not exposed to the 'good bacteria' in their mother's vagina. (Posed by models, Getty Images)

“From a clinical point of view, this transfer of microbial material is happening during a vaginal delivery,” said study author Dr Sture Andersson.

“This is a gift the mother gives to her baby.”

A baby’s immune system is not fully developed at birth, but strengthens once it enters the outside world and encounters relatively harmless pathogens, like cold viruses.

Studies have shown the good bacteria that colonise the gut differ between infants born vaginally or by C-section.

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These microbial variations are thought to affect how the immune system responds to allergens, like pollen, nuts and dust.

To test their proposal, the Helsinki scientists analysed seven pregnant women who were scheduled to have a C-section.

The enrolment criteria was stringent, with the team ensuring the mothers-to-be had no potentially dangerous infections, like group B streptococcus (GBS).

Pregnant women are not routinely tested for GBS in the UK. Around one in five mothers-to-be are thought to have the bacteria in their vagina or digestive tract, with most going on to have healthy babies. There is a small risk of complications, however, like sepsis.

Read more: Two in five with lung condition will shield until coronavirus vaccine

In the Helsinki study, faecal samples were collected, processed and frozen three weeks before the women’s C-section.

Shortly after birth, the babies had a faecal microbiota transplant (FMT). The first newborn to undergo the procedure received 7mg of microbial matter in 5ml of milk. Blood samples later revealed signs of inflammation, however, this quickly resolved with the infant appearing well.

Nevertheless, the remaining six babies had 3.5mg of microbial matter in 5ml of milk.

The transplant on average contained 7 million viable bacterial cells.

Watch: What is a faecal transplant?

After the FMT, the babies stayed in hospital for two days to ensure there were no complications.

The newborns’ meconium – the first stool, composed of materials ingested in the uterus – was tested to indicate their microbial levels at birth.

Faecal samples were again collected at two days, one week, two weeks, three weeks and three months.

Results, published in the journal Cell, revealed the babies had a similar microbial make-up at three months old as infants born vaginally.

Their gut bacteria also differed from babies born via C-section who did not have a FMT, as well as from their own mothers’ microbial make-up.

Read more: Dust, aerosols and cleaning products could worsen asthma

All of the infants were breastfed, except for one who switched to formula milk at two months old. Breastfeeding is known to also boost a baby’s gut health.

None of the infants showed any side effects.

“This was not designed as a safety study, but we found it to be effective and supporting the concept of vertical transfer from mother to baby,” said study author Dr Willem de Vos.

“However, it’s very important to tell people this is not something they should try on their own. The samples have to be tested for safety and suitability.”

What is faecal microbial transplantation?

FMT is only approved in the UK when other treatments have failed to stop diarrhoea caused by the bacteria Clostridium difficile.

This involves faeces being taken from a healthy donor and processed.

A liquid mixture is then transplanted into a patient’s intestine via an endoscope. The aim is to restore the balance of gut bacteria so they can fight the infection.

Donors are first tested for an array of infections. They must be free of health problems and lead a healthy lifestyle.

C. difficile can be tricky to treat, with up to a one in four chance of the infection returning after initially seeming to be cured.

The bacteria can become less responsive to antibiotics over time, prompting doctors to recommend FMT.

There have been no reported cases of infections as a result of a patient receiving the transplant.

Watch: Study sought super donors for faecal transplants