Birth studies: It is more beneficial to the immune system of babies to be born by a normal labour than as a result of a Caesarean section, new research suggests.
The findings are based on research which was carried out in Dublin by analysing blood samples taken from the placentas of babies born both vaginally and by Caesarean section.
Some 20 of the samples were taken from the placentas of babies born vaginally and 10 were from the placentas of babies born by Caesarean section.
One of the researchers, Dr William Watson, a lecturer in the Department of Surgery at the Mater Hospital and a researcher at the Conway Institute of Biomolecular and Biomedical Research at UCD, explained that a person's immune system is both innate and acquired.
The innate part of the immune system was looked at by examining neutrophils in the babies' bloods. These are a type of white blood cell that help kill and digest micro-organisms and fight bacterial infection.
"We were interested in whether during labour these neutrophils became activated so that they could fight infection much better," Dr Watson said.
And indeed they did. "We have shown that during labour the immune system is activated in the baby to fight bacterial infection," he said.
Labour of any duration was found to be beneficial. "There is a lot of evidence that neonates born by Caesarean section do have complications and we were interested in understanding why," he said.
The immune system of babies born by Caesarean section was not activated to the same extent.
The research was a collaborative effort between Our Lady's Hospital for Sick Children in Crumlin, Dublin; the Coombe Women's Hospital, Dublin; and the Conway Institute of Biomolecular and Biomedical Research at UCD.
Earlier research by the team, published in February in the American Journal of Obstetrics and Gynaecology, found that labour was also more beneficial to the mother's immune system.
Again, the length of the labour did not matter, the study found.
The latest research from the team, which has been published in the journal Paediatric Research would suggest women should think twice before electing for Caesarean sections.
The rate at which Caesarean sections are being performed has risen in recent years and a study published last year showed more than 20 per cent of Irish births are now by Caesarean section.
The World Health Organisation recommends a rate of 15 per cent.
Fear of the birth process is one reason why women seek Caesarean sections in what has been referred to as the "too posh to push" syndrome in Britain.
Some obstetricians refuse women's requests for unnecessary Caesarean sections on the grounds that there are always risks associated with surgery but women can then go to another hospital and find a consultant willing to carry out the procedure.
The National Institute for Clinical Excellence (NICE) in Britain recently issued guidelines saying pregnant women should be discouraged from having a Caesarean delivery if they do not need one. Around 1.5 per cent of all births in England and Wales are currently Caesareans carried out for "non-medical reasons".
The government body said women must be told about the risks and benefits of different ways of having a baby. However, doctors would ultimately have to allow a woman to choose how she gives birth.
A report by the influential health committee in the House of Commons last June said pregnant women should no longer be able to choose to have a Caesarean.