Feeding C-section newborns mother’s faeces may help to strengthen immune system, study suggests

Babies born via Caesarean section who are fed a small amount of their mother’s faeces in breast milk have a similar microbial makeup to babies born vaginally, a study suggests.

Typically, infants delivered by C-section have an increased risk of developing asthma and allergies as babies and toddlers.

This is likely because they are not exposed to the microbiota in the mother’s vagina and perineum during birth, which negatively impacts how their immune systems develop.

However, researchers found that a sample of seven newborns fed a small amount of their mother’s faeces had a microbial makeup that looked more similar to babies born vaginally than those born by C-section.

"From a clinical point of view, this transfer of microbial material is happening during a vaginal delivery," said one of the paper’s authors, Sture Andersson, of the Pediatric Research Center at the University of Helsinki and Helsinki University Hospital in Finland. "This is a gift the mother gives to her baby."

Although a baby’s immune system is undeveloped at birth, it quickly matures in response to microbial exposure in the outside world.

While every person’s microbiota is specific to them, the overall patterns of which bacteria colonise the gut are different in babies born vaginally and by C-section. The variations appear to make a difference in how the immune system learns to respond to outside stimuli including potential allergens, the researchers write.

Seven mothers who were scheduled to have C-sections took part in the study, published in the journal Cell.

Their babies were given feral microbiota transplants (FMTs) shortly after birth from samples which were collected from their mother’s three weeks beforehand.

The babies stayed in the hospital for two days after the transplants to make sure there were no complications, while their own focal microbiota was tested at birth and again after two days, one week, two weeks, three weeks and three months.

The investigators found that by three months the microbiota of the babies who received the FMTs were similar to those of babies born vaginally. They were different from those born by C-section and different from their mother’s microbiota.

"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 another of the study’s authors Willem de Vos, of the Human Microbiome Research Program at the University of Helsinki and the Laboratory of Microbiology at Wageningen University in the Netherlands.

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

In the future, the researchers plan to compare the development of the immune system between C-section babies who receive FMTs and those who do not.

They also said future studies will have a control group and the mothers will not know whether their child has received the FMTs.