Scientists said that despite picking up hospital superbugs, none of the babies born by C-section in the study became ill. Picture: Reuters

London - Babies born by caesarean section are at greater risk of picking up hospital superbugs than those born naturally, research suggests.

Newborns delivered by C-section picked up more "unhealthy" bacteria from hospitals, according to the study. But the guts of babies born naturally were rapidly colonised by their mother’s "healthy" bacteria – leaving less room for superbugs.

As well as the risk of infection, hospital bugs may affect the babies’ immune systems – making them more at risk of allergies, asthma and diabetes in later life.

Scientists said that despite picking up hospital superbugs, none of the babies born by C-section in the study became ill. This is because the bugs found in the babies’ guts only pose an immediate danger if they enter the bloodstream.

But the researchers warned they could still pose a threat to very sick infants.

They said that being colonised by hospital bugs was a "previously under-appreciated risk factor in hospital births".

They also found for the first time that the bacteria in babies matched those that came from their mother’s gut. Previous studies had suggested babies got their first bacteria as they are pushed through the birth canal.

Some women who undergo C-sections undergo "vaginal seeding" in the belief this can restore bacteria the baby misses out on when surgically removed. This involves taking a swab from the mother and applying it to the baby’s face.

But the study said this practice was pointless, because they were the wrong bacteria. Scientists from the Wellcome Sanger Institute, UCL and Birmingham University studied 600 healthy babies and 175 mothers, taking 1 679 samples of gut bacteria. Samples were taken from babies aged four, seven or 21 days old.

Babies born naturally had many more healthy bacteria than those born by caesarean, possibly because antibiotics taken during C-sections wipe out healthy bacteria, allowing "opportunistic" hospital bugs to move in.

Dr Nigel Field, clinical associate professor at UCL, said: "Babies are sterile when they are in the womb. And the moment they are born is the moment when the immune system has a huge number of bacteria that is it presented with. The hypothesis is that that moment of birth might be a sort of thermostat moment which sets the immune system for future life.

"There is research showing that babies born by caesarean section have a slightly higher risk of immune-related conditions. They have a slightly higher risk of asthma, or inflammatory bowel disease and other allergic conditions."

Dr Field added: "In summary, we found significant differences between babies born by caesarean and babies born vaginally, but these babies were healthy when they took part in the study, and we don’t know what the long-term consequences are."

Scientists found the differences in gut bacteria between naturally born and caesarean-delivered babies largely evened out after one year. But large follow-up studies are needed to determine if the early differences influence health outcomes.

Dr Trevor Lawley, a senior author on the paper from the Wellcome Sanger Institute, said: "Further understanding of which species of bacteria help create a healthy baby microbiome (bacteria community) could enable us to create bacterial therapies."

Experts from the Royal College of Obstetricians and Gynaecologists say the findings should not deter women from having a caesarean birth.

Daily Mail