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Study: C-sections less risky for babies than previously thought

Caesarean operations don't cause allergies but may be tied to asthma, a Finnish study found.

Vauvan vaippaa vaihdetaan.
Newborns who were cut out of their mothers have different microbiomes than vaginally born ones. Image: AOP

A long-term study published on Thursday found that caesarean deliveries do not carry the risks most commonly associated with them.

Researchers in Finland and Barcelona followed the health data of more than 1.4 million infants born in Finland from birth to adolescence, comparing those born by C-section with the rest. The study found no connection between the operation and a higher risk of children (born between 1990 and 2014) developing chronic problems such as allergies, Type I diabetes or obesity.

Researchers also found that caesarean did not increase the risk or rate of infant mortality, but could potentially compromise a baby's lungs.

"Our results suggest that avoidable unplanned C-sections increase the risk of asthma, but do not affect other immune-mediated disorders previously associated with C-sections," the abstract reads.

The study was conducted by the Institute for Economic Research (VATT), the Finnish Institute for Health and Welfare (THL) and researchers from the University of Turku and Pompeu Fabra University in Barcelona.

Previous studies inadequate

Researcher Lauri Sääksvuori pointed out the significance of the study's findings, saying that previous attempts to tie C-sections to long-term health risks were flawed.

"Prior research has tried to make connections by comparing children born by vaginal delivery with those born by C-section. However, we know that infants are very different from one another for a host of reasons, as well as the mothers giving birth. Our new method resolves all the problems associated with previous research," Sääksvuori said.

About 16 percent of children in Finland are born via caesarean section. THL reported that in 2018 doctors performed a little over 4,300 urgent C-sections and 390 emergency C-sections. A little over 3,100 scheduled caesarean operations were performed.

Urgent operations are for situations where a moderately serious problem arises that can be solved with a C-section, such as when the mother runs out of strength and cannot push. Emergency caesareans are for cases where the mother's and/or child's life is directly in danger, with only minutes to spare, such as when the baby's breathing is obstructed.

Different gut bacteria, implications unknown

A separate study published in Nature in September found that babies born by C-section have different gut bacteria than those born vaginally. Essentially, vaginally born babies received most of their gut bacteria (known collectively as the microbiome) from their mother, whereas C-section babies "had more bacteria associated with hospital environments in their guts", the press release reads.

The research conducted by scientists from the Wellcome Sanger Institute, University College London (UCL) and the University of Birmingham discovered the connection between microbiome make-up and delivery method, but the researchers were unable to pinpoint the implications of the different bacteria types.

"The exact role of the baby's gut bacteria is unclear and it isn't known if these differences at birth will have any effect on later health. The researchers found the differences in gut bacteria between vaginally born and caesarean delivered babies largely evened out by 1 year old, but large follow-up studies are needed to determine if the early differences influence health outcomes. Experts from the Royal College of Obstetricians and Gynaecologists say that these findings should not deter women from having a caesarean birth," UCL announced.

EDIT 18.10.2019 This story originally stated that "more than 1.4 million infants" were "born in Finland by emergency C-section". This is incorrect. 1.4 million is the total for live births, not the total of caesarean deliveries.

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