Research published today in PLOS Medicine has shown that infants born by caesarean section have an increased risk of hospital admission with infection during childhood. Potentially, new mothers can offset this risk through postnatal actions such as breast feeding and skin to skin contact.
In many countries, the proportion of babies born via caesarean section has increased over recent years. Information on long-term health outcomes for children born by caesarean section has been inconsistent, but a new study involving researchers from NDPH’s National Perinatal Epidemiology Unit (NPEU) and Big Data Institute (BDI) has found that babies born by caesarean are significantly more likely to be hospitalised for early childhood infections, compared with vaginally-born children.
The study was led by the Murdoch Children’s Research Institute and Aarhus University, and analysed over 7.17 million births which took place between 1996-2015 in Australia, Denmark, Scotland and England. Caesarean rates varied between these countries, but overall, 23% of the births took place by caesarean, of which 57% were emergency and 43% were elective.
In total, around 1.5 million (21%) of the children had at least one infection-related hospital admission before their fifth birthday. Compared to vaginally born children, children born by elective caesarean had a 13% increased risk for an infection-related hospitalisation, and emergency caesarean-born children had a 9% increased risk. Increased risks lasted throughout follow-up to five years of age and were highest for respiratory, gastrointestinal, and other viral infections.
Approximately 650,000 babies are born in England each year. Based on the findings of this study, around 135,000 will experience at least one infection-related hospital admission before their fifth birthday. Around 3,000-4,000 of those could be associated with caesarean delivery. ‘On a population level, these results are quite striking, since datasets from several countries all show the same thing, which points to a need to further investigate any mechanisms of action’, says Raph Goldacre, the epidemiologist who led the analysis in England.
It has been postulated that caesarean- and vaginally-born children are exposed to different microorganisms during delivery, since children born by caesarean do not come into contact with bacteria from the mother's gut and vagina. This would affect the composition of their early microbiome, and consequently the development of post-natal immune responses.
Professor Marian Knight says ‘Many factors influence the composition of the early microbiome, so mothers that have caesarean births should not be unduly worried. Postnatal actions, such as breastfeeding and skin to skin contact, can also influence the microbiome. Breastfeeding, for example, increases the proportion of friendly bacteria in the baby’s gut. We know breast-fed babies have lower levels of infections such as gastroenteritis. Encouraging breast feeding would therefore be an effective way to help reduce infections.’