Babies delivered by Caesarean section at higher risk of asthma and allergies
Researchers found significant differences in the gut bacteria found in infants born surgically and naturallyExclusively bottle-fed babies also had significant differences in their gut bacteria Previous research found children born surgically are at double the risk of obesity in childhood
17:37 GMT, 11 February 2013
17:43 GMT, 11 February 2013
Babies delivered by Caesarean miss out on protective bugs that could help prevent a host of disorders in childhood and later life, warn researchers.
They found significant differences in the gut bacteria found in infants born surgically and naturally.
Babies fed formula milk, rather than being breastfed, also lacked bacteria that may be protective, according to a new study in the Canadian Medical Association Journal.
Babies delivered by Caesarean miss out on protective bugs that could help prevent conditions such as asthma
Researchers said the findings would increase concern about potential lifelong effects for the baby from the soaring rate of Caesareans.
Although emergency Caesarean births can be life-saving, planned surgery is recognised as riskier for mothers because they are more likely to develop complications and spend twice as long in hospital as women having a natural delivery.
The latest study adds to worries about the hazards for infants after previous research suggested children born surgically are at double the risk of obesity in childhood, with a higher risk of developing type 1 diabetes and asthma.
Although the exact reasons are unknown, surgical babies may be missing out on physiological changes that happen during labour including exposure to bugs which are necessary for the immune system to mature.
The rate of surgical deliveries in England is almost 25 per cent, adding up to more than 190,000 a year. In some parts of London one in three hospital deliveries is by Caesarean.
The study looked at data on 24 healthy infants, as part of the larger Canadian Healthy Infant Longitudinal Development study, who were representative of Canadian newborns with 25 per cent born by Caesarean and 42 per cent breastfed exclusively at 4 months of age.
It's thought that surgical babies may be missing out exposure to bugs which are necessary for the immune system to mature
The researchers used new DNA sequencing technology to investigate the gut bacterial composition of the babies, a technique that allows detection of virtually all the bugs present.
Previous studies of this type have been conducted using laboratory cultures, which are limited as about 80 per cent of intestinal microbes cannot be grown in culture.
The researchers found infants born surgically were lacking a specific group of bacteria found in infants delivered naturally, even if they were breastfed.
Infants strictly formula-fed, compared with babies that were exclusively or partially breastfed, also had significant differences in their gut bacteria.
Co-author Dr Anita Kozyrskyj, of the University of Alberta, said: ‘Our findings are particularly timely given the recent affirmation of the gut microbiota as a ‘super organ’ with diverse roles in health and disease, and the increasing concern over rising Caesarean delivery and insufficient exclusive breastfeeding.’
The potential long-term consequences of decisions regarding mode of delivery and infant diet are ‘not to be underestimated’, said the study report.
‘Infants born by Caesarean delivery are at increased risk of asthma, obesity and type 1 diabetes, whereas breastfeeding is variably protective against these and other disorders’ it said.
Researcher Meghan Azad, of the University of Alberta, said: ‘We want parents (and physicians) to realize that their decisions regarding C-section and breastfeeding can impact their infant’s gut microbiome, and this can have potentially lifelong effects on the child’s health.’
Experts believe gut bacteria play a role in stimulating the immune system.
Because infants born surgically are not exposed to beneficial bacteria in the birth canal, they might take longer to accumulate good bugs, which delays exposure to microbes that kick start the immune system.
Dr Rob Knight, a scientist at the University of Colorado, Boulder, Colorado, United States, in a related commentary, said: ‘Children born by Caesarean delivery or fed with formula may be at increased risk of a variety of conditions later in life; both processes alter the gut microbiota in healthy infants, which could be the mechanism for the increased risk.’