A new study from Harvard T.H. Chan School of Public Health shows that babies born by cesarean delivery are at a 15 percent increased risk of developing obesity  than those born by natural vaginal birth. Moreover, babies born through C-section are also 64 percent more likely to be obese than their siblings who were delivered naturally.

The study, published online on Sept. 6 in JAMA Pediatrics,  says that the increased risk may persist through adulthood.  Moreover, people born through vaginal delivery among women who delivered through C-section are 31 percent less likely to become obese than those individuals born through cesarean delivery following a cesarean birth.

“I think that our findings—particularly those that show a dramatic difference in obesity risk between those born via cesarean and their siblings born through vaginal delivery—provide very compelling evidence that the association between cesarean birth and childhood obesity is real,” points out senior author Jorge Chavarro, an associate professor of nutrition and epidemiology at Harvard Chan School. “That’s because in the case of siblings, many of the factors that could potentially be playing a role in obesity risk, including genetics, would be largely the same for each sibling—except for the type of delivery.”


This was not the first time cesarean birth was linked with health problems, but previous research had limited data. This new study involved analyzing data of over 22,000 young adults in the Growing Up Today Study (GUTS).

The GUTS were taken every year or two years from 1996 to 2012. Participants had to answer survey questions. The data asked included the participants’ BMI, mode of delivery, age, smoking status, location and their BMI before they got pregnant.

Chavarro says that cesarean delivery is still necessary and could save lives in many cases despite its known risks to the mother and the newborn. Nevertheless, he says that their findings show that the risk of obesity in the child could be another factor to consider when undergoing the procedure.