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Research: Could Birth-Canal Bacteria Help C-Section Babies?

From a poster at the recent Boston meeting of the American Society of Microbiology. (Courtesy Dr. Dominguez-Bello)

From a poster at the recent Boston meeting of the American Society for Microbiology. (Courtesy Dr. Dominguez-Bello)

The usual drill is to wipe the effluvia of birth off of newborn babies, cleaning them up and readying them for snuggling.

But in a fascinating departure, researchers have begun to experiment with the opposite: collecting birth-canal bacteria and wiping them onto babies after birth.

Why in the world? For good reason: to explore whether it might help babies delivered by C-section to restore some of the vaginal bacteria that they would have been exposed to if they’d gone through the birth canal.

Why do that? On the theory that altered bacterial populations could help explain why C-section babies tend to have higher odds of asthma, allergies, obesity and other health risks.

Dr. Maria Gloria Dominguez-Bello, an associate professor in the Human Microbiome Program at the NYU School of Medicine, presented some preliminary results on that research at a recent conference of the American Society for Microbiology here in Boston. Those initial findings suggest that indeed, using gauze to gather a mother’s birth-canal bacteria and then impart them to babies born by C-section does make those babies’ bacterial populations more closely resemble vaginally born babies — though only partially.

Many questions remain. But the research sounded so intriguing — and the intervention so simple, if it gains medical approval — that I asked Dr. Dominguez-Bello to discuss it. Our conversation, edited:

Your poster reports that there were six vaginal births, seven C-sections and four C-sections in which the babies also received the ‘inoculum’ of vaginal bacteria. But it wasn’t clear to me: To what extent did the mothers’ bacteria restore a more normal balance of bacteria in the C-section babies? A little or a lot?

When we analyzed the sharing — how many microbes any site of the baby’s body share with their mom’s vagina — we doubled the number of bacteria that the C-section babies were exposed to. But the vaginal process was six times as much. So the vaginal delivery still exposes the baby to a lot more.

In other words, if we got one bacteria in the C-section baby that is associated with the vagina, we got two in the inoculated C-section but six in the vaginal births. So those C-section babies still don’t have the full exposure of the vaginal babies.

That’s logical because during labor, the baby is rubbing against the mucosa of the birth canal for a long time and bacteria start growing even before the baby is out — growing and colonizing the baby during birth. In half an hour, you get multiplication of bacteria. If the baby gets one cell, an hour later the baby has probably four of those cells and five hours later, it’s exponential.

Also, C-sections involve antibiotics. There is no C-section without antibiotics, and we don’t know what the effect is of that gram of penicillin. If it’s good enough to kill strep B, I’m sure it’s killing a lot more than that community of bacteria.

If your research pans out, using this gauze technique for C-section babies would seem to be such an easy intervention. I imagine there might already be women saying, ‘I want to do that.’ Possibly even, ‘I want to schedule a C-section and do that.’ What would you say to them?

I would say labor is a very complex process and labor is far more than inoculating the baby. And it’s a process that we don’t fully understand — what’s its adaptive value, why is it important? Continue reading