A baby in a neonatal intensive care unit. Photo courtesy Miracle Babies
A baby in a neonatal intensive care unit. Photo courtesy Miracle Babies

Researchers at the UC San Diego School of Medicine Monday announced a tentative discovery into how babies born by Caesarean section become vulnerable to certain medical conditions.

Their study of 18 babies, in partnership with the Icahn School of Medicine at Mount Sinai in New York, found that newborns born via C-section don’t receive microbes from their mothers’ vaginas. The research, which appears in the journal Nature Medicine, suggests that such microbes help develop immune systems in babies.

Previous research suggested a link between C-section delivery and increased subsequent risk of obesity, asthma, allergies, atopic disease and other immune deficiencies, according to the scientists. Many of those diseases have been linked to the microbiome, though the role a newborn’s microbiome plays in current or long-term health is not yet well-understood.

“When my own child was born by unplanned C-section, we took matters into our own hands to see to it that she was exposed to vaginal microbes,” said Rob Knight, a professor of pediatrics, computer science and engineering at UC San Diego.

“She is now 4 years old and healthy, but that was an uncontrolled experiment of one and so we can’t tell whether it had an effect from a scientific perspective,” said Knight, who is also director of the Center for Microbiome Innovation.

“This study now starts to prove that the effect exists, telling us that some of those vaginal microbes probably do stick around when transferred to a baby born by C-section, at least for the first month of life,” he said.

Knight said other research suggests that microbiome differences between vaginal and C-section babies can persist for years.

Knight and researchers from the Icahn School, New York University, University of Colorado-Boulder and University of Puerto Rico studied seven babies born vaginally and 11 delivered by scheduled C-section.

Of the C-section babies, four were swabbed on their mouth, face and body with a sterile gauze that was incubated in the mothers’ vaginas for one hour before birth. The others were not swabbed.

The scientists subsequently collected more than 1,500 samples taken on six occasions over the first month after delivery.

After using a gene sequencing technique to map the types and quantities of bacterial species that were present, they found that the microbiomes of the four C-section-delivered infants exposed to vaginal fluids more closely resembled those of infants born normally, compared to the unexposed C-section- delivered infants.

The difference was still noticeable one month after birth, the researchers said.

“The present work is a pilot study — we need substantially more children and a longer follow-up period to connect the procedure to health effects,” Knight said.

“This study points the way to how we would do that, and provides the proof-of-concept that microbiome modification early in life is possible,” he said. “In fact, we already have more than 10,000 additional samples collected as part of this study that still await analysis.”

The research was funded by the National Institutes of Health, C&D Research Fund, Crohn’s and Colitis Foundation of America and the Icahn School. The scientists are seeking additional funding to continue their study.

—City News Service

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