Caesarean birth linked to risk of obesity in childhood – Research

Infants delivered by caesarean section may face a higher risk of becoming obese, a new study suggests. These babies had a 15 percent higher risk of becoming obese in childhood, compared with those born vaginally. The risk was even more pronounced within families, where children born by caesarean delivery were 64 percent more likely to become obese than their siblings who were born via vaginal delivery, the researchers said.

“What makes our findings compelling and different from previous studies addressing this question is that this was also true when we compared siblings who differed in type of delivery -- one was born by caesarean and the other by vaginal delivery -- and when restricted to women without any known risk factors for having a caesarean, some of whom may have undergone an elective caesarean,” said lead researcher Dr. Jorge Chavarro. He is an associate professor in the departments of nutrition and epidemiology at Harvard T.H. Chan School of Public Health in Boston.

The researchers also found that children born vaginally to women who had previously had a caesarean delivery were 31 percent less likely to be obese, compared with children born to women who had several caesarean deliveries.

But these findings only show which can lead to permanent vision loss, the study authors said.

“Even though we didn’t find live virus in mouse tears, that doesn’t mean that it couldn’t be infectious in humans,” said study lead author Dr. Jonathan Miner, an instructor in medicine. “There could be a window of time when tears are highly infectious and people are coming in contact with it and able to spread it.”

Samples of mouse tears were taken 28 days after infection, according to the researchers.

The immune system is less active in the eye in order to avoid accidental damage to sensitive tissues responsible for vision when the body is fighting an infection. This means infections sometimes persist in the eye after they have been an association between caesarean delivery and childhood obesity, not cause and effect.

Chavarro, however, believes the association is very strong. “These results, and in particular those regarding discordant siblings, strongly suggest that the association between caesarean delivery and childhood obesity is real, rather than an issue of inadequate control for shared causes as we and others had proposed,” he said.

As important as caesareans are, they are not without risks, Chavarro noted. “Our results point to a risk to eliminated from the rest of the body, the study authors explained.

Study co-senior author Dr. Rajendra Apte said the researchers “are planning studies in people to find out whether infectious virus persists in the cornea or other compartments of the eye, because that would have implications for corneal transplantation.” Apte is a professor of ophthalmology and visual science.

Even if further studies find that Zika cannot be transmitted through human tears, it may be possible to test tears for Zika genetic material or antibodies to offer a less painful way to diagnose recent Zika infection than the current method of taking blood samples, the researchers said.

Also, the eyes of mice could be children that is preventable in the case of caesareans that are strictly elective or when an indication is not clear,” he said.

The report was published online Sept. 6 in the journal JAMA Paediatrics.

For the study, Chavarro and his Harvard colleagues collected data on more than 22,000 children born to more than 15,000 women. Among these children, nearly 5,000 were delivered by caesarean section. These children were followed from childhood through early adulthood.

Mothers, who had caesarean delivery weighed more before pregnancy and were more likely to have pregnancy-induced diabetes, preeclampsia and high blood pressure, the researchers discovered.

“These findings add to the growing list of problems that babies have who are born by caesarean delivery, compared to vaginal delivery, including childhood asthma, pulmonary problems -- a whole host of things,” said Dr. Mitchell Maiman, chairman of the department of obstetrics and gynaecology at Staten Island University Hospital in New York City.

Maiman said these problems arise from not exposing the infant to the helpful bacteria in the vagina that gives the baby “an immunologic advantage as compared with babies born via caesarean delivery.”

The study authors concurred, saying that although evidence is still building, “this early life difference in mode of delivery leads to an altered gut microbiota pattern in offspring.”

Nearly 1.3 million caesarean deliveries are done each year in the United States. The rate of caesarean delivery ranges from 30 percent to 33 percent. “That’s way too high,” Maiman said. “The rate should be around 15 percent.”

“We need to make mothers aware that caesarean deliveries are not just bad for them, but bad for the babies, too,” Maiman said.