After one C-section, the risk of rupturing the scar often makes it necessary to deliver by C-section subsequently.
Worldwide, rates of C-section delivery range from 1-52%. After having one C-section, most women are likely to follow up with another one.
Once a baby has been delivered by C-section, any subsequent vaginal delivery could cause the scar to rupture, potentially leading to hypoxic brain injury in the infant. Therefore, a woman who has already delivered a child by C-section is often directed toward a C-section delivery next time.
Studies have suggested that infants delivered by C-section may have poorer long-term health outcomes because they miss the chance of exposure to maternal bowel flora during labor that is available during a vaginal birth.
However, the precise long-term health impact of a C-section delivery is not known.
Similar health outcomes after planned C-section and vaginal delivery
Mairead Black and colleagues, from the University of Aberdeen in the UK, compared health outcomes for children who were born by planned and unplanned C-section with children delivered vaginally after the mother had previously delivered a child by C-section.
- In 2014, there were 2,699,951 vaginal deliveries in the US
- 1,284,551 babies were born by C-section
- 32% of all deliveries were by C-section.
The researchers studied 40,145 second deliveries that took place in Scotland from 1993-2007, where the mothers had previously delivered a child by C-section.
Of these births, 44.6% were classed as "scheduled repeat C-section," or planned C-section, 22.1% were "unscheduled repeat C-section," or unplanned C-section, and 33.3% were vaginal births after previous cesarian.
The team compared the types of birth with a number of health outcomes.
These included: obesity at the age of 5 years, asthma leading to hospitalization and/or inhaler use at the age of 5 years, irritable bowel disease serious enough to warrant hospitalization, type 1 diabetes, cancer, cerebral palsy, learning disability and death.
Apart from a higher rate of asthma leading to hospitalization among those born by C-section, there appeared to be no substantial difference in health outcomes.
Moreover, since the rate of salbutamol inhaler use did not vary between the groups, the team concluded that this was not a significant difference.
Higher risk with unplanned C-section
Learning disability and death were more likely among children born by unscheduled C-section but not in those whose C-section delivery was planned. This could be the result of complications during delivery.
One limitation of the study is that the researchers did not know whether the initial plan for any of the births was to be vaginal or C-section.
They took an "intended C-section" to mean that C-section was scheduled in advance and happened on the pre-arranged date. When this was not the case, the C-section was classed as unplanned.
Cases of unplanned C-section were probably a combination of planned C-section brought forward due to an emergency, or planned vaginal birth that ended as an emergency C-section due to complications.
Meanwhile, the authors say:
"Women may be somewhat reassured by the apparent lack of risk to long-term offspring health following planned repeat [C-section] specifically. This study may, therefore, support the process of planning birth after C-section in a way that reflects women's values and preferences."
They also call for further investigations of rarer outcomes, such as cerebral palsy, to establish whether the risks are higher among particular delivery groups.
Medical News Today reported last year that on a national level, 19% would represent an appropriate rate of cesarian section delivery to ensure safety.