Babies who were delivered by cesarean section at birth may have increased risk of becoming obese.

Findings of a new study have found that babies who were born by cesarean section are at 15 percent increased risk of becoming obese in childhood than their peers who were born vaginally. Researchers said that this risk may persist through adulthood.

The increased risk was also found to be more pronounced within families, where children who were born by cesarean delivery had 64 percent increased likelihood to have weight problems than their siblings who were born via vaginal delivery.

Study researcher Jorge Chavarro, from the Harvard T.H. Chan School of Public Health in Boston, and colleagues discovered that individuals who were delivered via vaginal birth following a cesarean delivery by the mother had 31 percent reduced risk of becoming obese compared with individuals born via cesarean following another cesarean birth.

Nearly 1.3 million cesarean births are performed in the U.S. per year and these accounts for 30 to 33 percent of all deliveries in the country despite that the rate of cesarean birth should only be at 15 percent.

While cesarean delivery can be deemed necessary and lifesaving in many cases, the procedure is associated with risks to both the mother and the offspring.

A 2014 study involving 832,996 women, for instance, found that cesarean delivery may increase a woman's likelihood to experience stillbirth and ectopic pregnancy in future. Another study also found an association between pre-labor cesarean delivery and increased risk for childhood leukemia in the offspring.

Chavarro said that the findings of the study show that the obesity risk in the offspring could be another factor to be considered for cesarean births.

"Although additional research is needed to clarify the mechanisms underlying this association, clinicians and patients should weigh this risk when considering cesarean delivery in the absence of a clear indication," the researchers wrote.

Earlier studies have already found an association between cesarean birth and greater obesity risk in offspring but these either lacked detailed data or were too small to find a clear association.

The new study, however, used data taken over a span of 16 years and involved more than 22,000 participants. The researchers said that their study offers compelling evidence for the association given the difference in obesity risk they have identified among 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," Chavarro explained.

The study was published in the journal JAMA Pediatrics on Sept. 6.

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