They don't have a higher proportion of body fat - rather, it seems that their bones, fat and tissues just grow much more than vaginally-born mice.
In the new study, Dominguez-Bello and colleagues tracked the weight of 34 mice born by C-section and 35 mice born vaginally for 15 weeks.
RG: Would it be possible to expose mice or children born by C-section to the microbes they'd encounter in a vaginal birth?
According to study author Dr Maria Dominguez-Bello, this the first such study to demonstrate a causal relationship between c-section and increased body weight in mammals.
A study conducted by the New York University states that kids born via c-section are more likely to be obese adults. I recommend not to opt for a C-section when not medically necessary.
Along with a rise in C-sections, researchers are also seeing a rise in obesity, type-1 diabetes, allergies, and other immune-related diseases, suggesting C-sections may be related to such diseases. Conducted on mice, it found that rodents born via c-section are more likely to have an unbalanced amount of good and bad bacteria in their stomachs, which basically increases their chances of gaining weight.
Babies born by C-section are thought to miss out on these bacteria, which could explain why their microbiomes look different. This change is credited to the fact that bacteria in the stomach of these two groups of mice had grown differently. C-section male mice gained only 14 percent more weight compared with their vaginally delivered counterparts.
However, that of mice born by c-section, matured too quickly at first and then regressed later in their lives.
Dominguez-Bello: We think it's microbes, but we need to prove it. "We were very surprised to see this", she says. Mice born naturally had intestinal bacteria progress normally through the course of the study. One is that they did not use perinatal antibiotics, but the team expects that antibiotics, combined with C-section, could contribute to the weight gain.