Caesarean allergy risk studied

Birth by Caesarean section could leave children vulnerable to allergies and bowel disease, according to a new study.

Swedish researchers have shown how babies born by this route acquire a limited range of gut bacteria.

The researchers say their study has confirmed theories that this is one of the key ways in which children are put at a disadvantage by being born by this means.

Reporting in the journal Gut, the researchers say Caesarean babies take at least two years to develop the mixture of gut bacteria that other children acquire through natural birth.

Researchers compared nine children born through Caesarean section and another 15 delivered naturally.

They say there was an especial lack of diversity in the Bacteroidetes group of bacteria, which are thought to provide special protection against allergy.

There was also evidence of low levels of some immune system T cells, the researchers report.

The theory has already led to a project in Puerto Rico where midwives are smearing babies born through Caesarean with bacteria taken from their mother.

Researcher Professor Maria Jenmalm, who is professor of experimental allergology at Linköping University, Sweden, said: “Sometimes Caesarean sections are necessary. But it is important that both expectant mothers and doctors are aware that such a delivery may affect the child’s health."

Decreased gut microbiota diversity delayed Bacteroidetes colonisation and reduced Th1 responses in infants delivered by Caesarean section Gut 8 August 2013; doi 10.1136/gutjnl-2012-303249 [abstract]