It has been suggested that the type of delivery is a potentially powerful influence upon long-term health, may affect later life body mass index (BMI).
Researchers from the Imperial College London conducted a systematic review and meta-analysis of the effect of Caesarean section (CS) and vaginal delivery (VD) on offspring BMI, overweight (BMI>25) and obesity (BMI>30) in adulthood. This new study included data from 10 countries that was obtained from a search for any article published before 31st March 2012, in Pubmed, Google Scholar and Web of Science.
The researchers identified 35 studies and 15 studies with a combined population of 163,753 were suitable for inclusion in the meta-analysis.
The researchers found that the average BMI of adults born by caesarean section is around half a unit more than those born by vaginal delivery and an increased odds of overweight and obesity >20%; these findings are consistent across sexes.
In their conclusion the researchers write “There is a strong association between CS and increased offspring BMI, overweight and obesity in adulthood. Given the rising CS rate worldwide there is a need to determine whether this is causal, or reflective of confounding influences.”
The researchers note that findings from their meta-analysis are consistent with findings from other investigators. Shortly after completing their review a meta-analysis published in the International Journal of Obesity (July 2013) presented adult data from 3 studies that specifically examined the effect of mode of delivery and offspring overweight/obesity. The results reported 50% higher odds of obesity in adults born by CS compared to their VD counterparts from a systematic review and meta-analysis.
The authors note that they cannot be certain that caesarean delivery causes higher body weight, as the association may be explained by other factors that were not recorded in the data they analyzed.
Professor Neena Modi, Professor of Neonatal Medicine at Imperial College London and senior author of study commented “There are good reasons why C-section may be the best option for many mothers and their babies, and C-sections can on occasion be life-saving. However, we need to understand the long-term outcomes in order to provide the best advice to women who are considering caesarean delivery.”
“This study shows that babies born by C-section are more likely to be overweight or obese later in life. We now need to determine whether this is the result of the C-section, or if other reasons explain the association.”
Dr. Matthew Hyde, Research Associate in the Section of Neonatal Medicine, Faculty of Medicine, Imperial College London and corresponding author of this commented “There are plausible mechanisms by which caesarean delivery might influence later body weight. The types of healthy bacteria in the gut differ in babies born by caesarean and vaginal delivery, which can have broad effects on health. Also, the compression of the baby during vaginal birth appears to influence which genes are switched on, and this could have a long-term effect on metabolism.”
This meta-analysis is published in PLOS ONE.
Materials provided by The Imperial College London