Children born by cesarean are at greater risk of becoming overweight in adolescence, compared with children born vaginally in the traditional way, according to new research presented at a meeting organized by the American Heart Association in New Orleans.

A team of researchers at the Johns Hopkins University have analyzed data from 1,441 births performed both vaginally and by Caesarean section. They later measured and estimated the proportion of the children that were overweight or obese when 2 to 8 years of age. It turned out that obesity was 40 percent more common among children who were given birth by c-section.

“We think that the reason for the difference may be due to the beneficial microbes found in the birth canal that newborns are exposed to during a vaginal birth,” said Noel Mueller, assistant professor of epidemiology at Johns Hopkins University who led the study.

The study also took into account factors such as maternal age, education, finance, weight before and during pregnancy, the baby’s weight at birth and exposure to air pollution during childhood.

“We suspect that these microbes may benefit a child’s health, including enhancing metabolism and training the immune system.”, Mueller adds that “We need more studies to determine whether exposing cesarean-delivered newborns to vaginal microbes at birth can reduce their future risk of metabolic disorders such as obesity.”

C-section has become the most common surgical procedure among women of childbearing age. It is on the rise everywhere around the world, increased by 60% from 1996 to 2009 in the U.S. China has been cited as having the highest rates of C-sections in the world at 46% as of 2008.

Reference:

American Heart Association Meeting Report – Presentation 152 – Session: LF.AOS.475.N