Children born by cesarian may display certain neurodevelopmental differences to those born by more traditional methods, according to a study on mice recently published in the journal Proceedings of the National Academy of Sciences.
Researchers at Georgia State University monitored the brain activity of mice pups to compare the effects of cesarean and vaginal birth delivery on neuronal cell death from birth to weaning age. They found that those born by C-section displayed higher rates of cell death than those born via vaginal birth.
For the study, the researchers selected pregnant female mice for cesarian at random. Each pup was then paired with a peer who had been born by vaginal delivery, matching the gestation period and circadian time to keep the experiment fair.
An imaging technique called immunohistochemistry was used to monitor levels of a protein called caspase-3 (also a marker of cell death) before and after birth. Interestingly, the results revealed a decrease in cell death in the brains of pups born by vaginal delivery but no change or increase in those born by cesarian. The disparity was particularly noticeable in a region of the brain called the hypothalamus, which is responsible for regulating responses to stress and brain-immune interactions.
This is important because cell development is a major developmental process that happens in the first few weeks outside the womb, both in mice and humans. In mice, roughly half of all neurons initially produced are destroyed as a result.
Later examination showed that nine out of 13 brain regions, again, had elevated rates of cell death in the cesarian born mice. None showed the opposite.
On a biological level, this meant that the pups delivered by C-section had lower numbers of brain neurons. On a behavioral level, this was displayed in the vocalization calls observed in a maternal separation test – all pups emit distress calls when they have been separated from their mother and litter mates, but those who had been born by cesarian made noises of lower amplitude in comparison to their peers.
On other measures of development (say, total brain size and day of eye-opening), the researchers observed no noticeable differences between the two birth groups. They did, however, point out that those born by cesarian put on more weight by the time they hit weaning age than those born by vaginal delivery.
The experiment was a mouse model, so it is not entirely clear how the results will apply to human children, but it does seem to back up previous studies comparing C-sections to vaginal births, including one that found babies born by cesarian are more likely to be obese as children. Others have linked C-sections to chronic disease, food allergies, and asthma.